The rod guide and solids control assembly can be mounted on a rod string. The assembly can allow well fluid that contains high solids to pass through the pump under normal operation while eliminating the solids from being swept back into the pump barrel. The assembly can include a body portion coupled to a bristle that extends helically around the body portion. The body portion can be placed on a pump valve rod or hollow valve rod. On an upstroke, the bristles can be locked into place for trapping and lifting the solids. On a downstroke, the bristles can be rotated for leaving the solids higher and away from a pump intake. This can allow the solids to be lifted out of the pump and thereby prevent solids from collecting on a bottom portion of the pump. Multiple assemblies can be incorporated into the sucker rod string.

Oil well pumping systems are well known in the art. Such systems can be used to mechanically remove oil or other fluid from beneath the earth's surface, particularly when the natural pressure in an oil well has diminished. Generally, an oil well pumping system can begin with an above-ground pumping unit, which can be commonly referred to as a "pumpjack," "nodding donkey," "horsehead pump," "beam pump," "sucker rod pump," and the like. The pumping unit can create a reciprocating up and down pumping action that moves the oil or other substance being pumped out of the ground and into a flow line, from which the oil can then be taken to a storage tank or other such structure.
Below the ground, a shaft can be lined with piping known as "tubing." Into the tubing is inserted a string of sucker rods, which ultimately can be indirectly coupled at its north end to the above-ground pumping unit. The string of sucker rods can be indirectly coupled at its south end to a subsurface pump that is located at or near the fluid in the oil well. The subsurface pump can have a number of basic components, including a barrel and a plunger. The plunger can operate within the barrel, and the barrel, in turn, can be positioned within the tubing. It is common for the barrel to include a standing valve and the plunger to include a traveling valve. The north end of the plunger can be typically connected to a valve rod, which moves up and down to actuate the pump plunger. The valve rod can pass through a guide positioned at the north end of the barrel, which assists in centering the valve rod and thereby, the plunger. In addition, the guide can include openings through which the oil or other substance being pumped can exit the pump barrel and travel into the tubing.
There are a number of problems that can occur during oil pumping operations. Fluid that is pumped from the ground is generally impure, and includes solid impurities such as sand, pebbles, limestone, and other sediment and debris. Certain kinds of pumped fluids, such as heavy crude, tend to contain a relatively large amount of solids. Because of this, several disadvantages exist with prior valve rods. For example, after the solids have been exhausted from the pump barrel and the pump has temporarily discontinued pumping operations, the solids can naturally begin to settle due to gravity. With prior art valve rods, the solids are able to reenter the pump barrel at this time. This often results in excessive barrel wear upon restarting of the pump. Furthermore, it is possible that with the solids reentering the pump barrel, they can cause sticking of the pump i.e., seizing the plunger in the barrel.
Conventional pumps discharge fluid into the tubing allowing the fluid to move to the surface. On upstrokes, the well fluid through the pump can discharge to the top valve rod guide. When the plunger moves downward back into the barrel, the open cage atop the pump can allow fluid that was just discharged to reenter the barrel through the rod guide. The fluid discharged into the tubing from the pump can contain solids that concentrate themselves into the first two or three joints of tubing due to gravity. The fluid contained in this section of tubing can be concentrated and contain a higher percentage of solids than the fluid that was just discharged thus introducing additional solid impurities that create additional damage to both the barrel and plunger. Furthermore, the string of sucker rods reciprocating in an up and down movement can cause the rod to rub on the tubing typically made of steel. This can cause failure of the tubing resulting in leaking of fluid and thereby preventing fluid from reaching the surface.
The present disclosure relates to a rod guide and solids control assembly for use with conventional rod pumps for preventing or reducing the amount of solids from reentering back into the pump. It addresses the problems encountered in prior art pumping systems as well as provides other, related advantages.


A time-interleaved analog-to-digital converter that samples an analog input signal at a sampling frequency and converts the analog input signal into a digital output signal is enabled to perform correction processing on an error by: converting the analog input signal into the digital output signal by a plurality of analog-to-digital conversion circuits in a time-interleaved manner; and performing gain correction processing and skew correction processing with respect to the analog-to-digital conversion circuit, on the basis of a mixed signal, the mixed signal being obtained by mixing an output signal from the analog-to-digital conversion circuit with a signal made by shifting a phase of the output signal by π/2.

A time-interleaved analog-to-digital converter (ADC) is an ADC that includes a plurality of analog-to-digital conversion circuits (AD conversion circuits), and the plurality of AD conversion circuits sequentially convert an analog input signal into a digital output signal in a time division manner and can realize high-speed operation. However, the time-interleaved ADC sometimes deteriorates in AD conversion accuracy due to a gain mismatch (difference in amplitude in each AD conversion circuit) or a skew (deviation in timing interval when each AD conversion circuit operates) between the AD conversion circuits.
As a method of correcting an error between the plurality of AD conversion circuits in the time-interleaved ADC, various methods are proposed (see, for example, Patent Documents 1 to 3, and Non-Patent Document 1). Further, there are foreground correction of performing correction processing on the error outside the normal operating time of the ADC and background correction of performing correction processing on the error during the normal operation of the ADC. In the background correction, a detection operation and a correction operation for the error can be performed without hindering a normal AD conversion operation.
FIG. 8 is a diagram illustrating a configuration example of a conventional time-interleaved ADC including a gain correction function and a skew correction function. The time-interleaved ADC includes a plurality of AD conversion circuits 801A, 801B. Assuming that the input signal into the time-interleaved ADC is cos(ωinnT+θ), an output signal y(n) from each of the AD conversion circuits 801A, 801B is expressed by the following Expression (1). When the gain of the AD conversion circuit 801A is G1 and the gain of the AD conversion circuit 801B is G2 in the Expression (1), G=(G1+G2)/2, ΔG=G1−G2. Further, ωin is an input angular frequency, ωs is an operating angular frequency (sampling angular frequency) of the time-interleaved ADC, and T is an operation cycle of the time-interleaved ADC. Further, θ is an initial phase and n is an integer equal to or larger than 0.
                              [                      Math            .                                                              1                    ]                                                                                y                                                  (                  n                  )                                            =                                                                            [                                      G                    +                                                                                (                                                      -                            1                                                    )                                                n                                                                                Δ                                                                                G                                                2                                                                              ]                                                                  cos                                                        (                                                                                ω                                                      i                                                                                n                                                                                nT                                            +                      θ                                        )                                                                                =                                                                            [                                      G                    +                                                                                Δ                                                                                G                                                2                                                                                cos                                                                          (                                                                                ω                                s                                                                                nT                                                        2                                                    )                                                                                ]                                                                  cos                                                        (                                                                                ω                                                      i                                                                                n                                                                                nT                                            +                      θ                                        )                                                                                =                                                                                G                                                                                cos                                                                    (                                                                                ω                                                              i                                                                                n                                                                                nT                                                    +                          θ                                                )                                                                                ︸                                          input                                                                                component                                                                      +                                                                                Δ                                                                                G                                            2                                                            cos                                                              {                                                                                (                                                                                ω                                                                  i                                                                                n                                                                                -                                                                                ω                                  s                                                                2                                                                                )                                                                              nT                                                +                        θ                                            }                                                                            ︸                                          image                                                                                component                                                                                (        1        )
By multiplying the output signal y(n) by (−1)n by a multiplier 904 of a gain correction unit 802 illustrated in FIG. 9, a signal yc(n) expressed by the following Expression (2) is obtained. Multiplying the output signal y(n) by (−1)n corresponds to frequency shift of a sampling frequency fs/2 (fs=ωs/2π).
                              [                      Math            .                                                              2                    ]                                                                                y                  c                                                                  (                  n                  )                                            =                                                                                (                                          -                      1                                        )                                    n                                ·                                  y                                                        (                    n                    )                                                                                =                                                                            cos                                                        (                                                                                ω                          s                                                                        nT                                            2                                        )                                                                                {                                                            G                                                                                cos                                                                          (                                                                                ω                                                                  i                                                                                n                                                                                nT                                                        +                            θ                                                    )                                                                                +                                                                                Δ                                                                                G                                                2                                                                                cos                                                                          [                                                                                (                                                                                ω                                                                          i                                                                                n                                                                                -                                                                                ω                                      s                                                                        2                                                                                )                                                                                nT                                                        +                            θ                                                    ]                                                                                }                                                                                =                                                                            G                                                                                cos                                                              [                                                                                (                                                                                ω                                                                  i                                                                                n                                                                                -                                                                                ω                                  s                                                                2                                                                                )                                                                              nT                                                +                        θ                                            ]                                                                      +                                                                            Δ                                                                                G                                        2                                                                          cos                                                              (                                                                                ω                                                          i                                                                                n                                                                                nT                                                +                        θ                                            )                                                                                (        2        )
Then, by multiplying the output signal y(n) by the signal yc(n) by a multiplier 905 of the gain correction unit 802, an output expressed by the following Expression (3) is obtained.
                              [                      Math            .                                                              3                    ]                                                                                y                                      (              n              )                                ·                                    y              c                                                  (              n              )                                      =                                            {                                                G                                                                                cos                                                              (                                                                                ω                                                          i                                                                                n                                                                                nT                                                +                        θ                                            )                                                                      +                                                                            Δ                                                                                G                                        2                                                                          cos                                                              [                                                                                (                                                                                ω                                                                  i                                                                                n                                                                                -                                                                                ω                                  s                                                                2                                                                                )                                                                              nT                                                +                        θ                                            ]                                                                                }                        ×                          {                                                G                                                                                cos                                                              [                                                                                (                                                                                ω                                                                  i                                                                                n                                                                                -                                                                                ω                                  s                                                                2                                                                                )                                                                              nT                                                +                        θ                                            ]                                                                      +                                                                            Δ                                                                                G                                        2                                                                          cos                                                              (                                                                                ω                                                          i                                                                                n                                                                                nT                                                +                        θ                                            )                                                                                }                                =                                                                      G                  2                                2                                                          {                                                      cos                                                              [                                                                                (                                                                                2                                                                                ω                                                                      i                                                                                n                                                                                -                                                                                ω                                  s                                                                2                                                                                )                                                                              nT                                                +                                                  2                                                    θ                                                                    ]                                                        +                                      cos                                                              (                                                                                ω                            s                                                                              nT                                                2                                            )                                                                      }                                      +                                                                                G                    ·                    Δ                                                                                G                                4                                                          {                                                      cos                                                              [                                                                                (                                                                                2                                                                                ω                                                                      i                                                                                n                                                                                -                                                              ω                                s                                                                                )                                                                              nT                                                +                                                  2                                                    θ                                                                    ]                                                        +                  1                                }                                      +                                                                                G                    ·                    Δ                                                                                G                                4                                                          {                                                      cos                                                              (                                                                        2                                                                                ω                                                          i                                                                                n                                                                                nT                                                +                                                  2                                                    θ                                                                    )                                                        +                  1                                }                                      +                                          1                2                                                                            (                                                            Δ                                                                                G                                        2                                    )                                2                                                          {                                                      cos                                                              [                                                                                (                                                                                2                                                                                ω                                                                      i                                                                                n                                                                                -                                                                                ω                                  s                                                                2                                                                                )                                                                              nT                                                +                                                  2                                                    θ                                                                    ]                                                        +                                      cos                                                              (                                                                                ω                            s                                                                              nT                                                2                                            )                                                                      }                                                                        (        3        )
In the case where the angular frequency ωin of the input signal is not ¼ of the operating angular frequency ωs of the time-interleaved ADC, terms of the trigonometric function, when averaged, can be recognized to be 0 in Expression (3). Therefore, an output from an accumulative adder 906 of the gain correction unit 802 that accumulatively adds the output y(n)·yc(n) from the multiplier 905 becomes as expressed in the following Expression (4). Using a detection value for gain correction, a multiplier 901 of the gain correction unit 802 performs gain correction.
                              [                      Math            .                                                              4                    ]                                                                                y                                            (                n                )                                      ·                                          y                c                                                          (                n                )                                              _                =                                                                              G                  ·                  Δ                                                                                G                            4                        +                                                            G                  ·                  Δ                                                                                G                            4                                =                                                    G                ·                Δ                                                                                G                        2                                              (        4        )
On the other hand, in the case where the angular frequency ωin of the input signal is ¼ of the operating angular frequency ωs of the time-interleaved ADC, when ωin=ωs/4 is substituted into Expression (3), the output y(n)·yc(n) from the multiplier 905 becomes as expressed in the following Expression (5).
                              [                      Math            .                                                              5                    ]                                                                                y                                      (              n              )                                ·                                    y              c                                                  (              n              )                                      =                                                            G                2                            2                                                  {                                                cos                                                                                2                                    θ                                +                                  cos                                                        (                                                                                ω                          s                                                                        nT                                            2                                        )                                                              }                                +                                                                      G                  ·                  Δ                                                                                G                            4                                                  {                                                cos                                                        (                                                                  -                                                                                ω                              s                                                                                nT                                                    2                                                                    +                                              2                                                θ                                                              )                                                  +                1                            }                                +                                                                      G                  ·                  Δ                                                                                G                            4                                                  {                                                cos                                                        (                                                                                ω                            s                                                                              nT                                                2                                            +                                              2                                                θ                                                              )                                                  +                1                            }                                +                                    1              2                                                                  (                                                      Δ                                                                                G                                    2                                )                            2                                                  {                                                cos                                                        (                                          2                                            θ                                        )                                                  +                                  cos                                                        (                                                                                ω                          s                                                                        nT                                            2                                        )                                                              }                                                          (        5        )
Through averaging by the accumulative adder 906, the detection value for gain correction becomes different from that in Expression (4) as illustrated in the following Expression (6).
                              [                      Math            .                                                              6                    ]                                                                                y                                            (                n                )                                      ·                                          y                c                                                          (                n                )                                              _                =                                                            G                2                            2                                    cos                                                                          2                        θ                    +                                                    G                ·                Δ                                                                                G                        2                    +                                    1              2                                                                  (                                                      Δ                                                                                G                                    2                                )                            2                                    cos                                                                          2                        θ                                              (        6        )
If the multiplier 901 of the gain correction unit 802 performs gain correction using the detection value for gain correction, accurate error correction is not performed. Hence, a notch filter 903 that has a frequency characteristic as illustrated in FIG. 10 to reduce a component of ωs/4 is conventionally provided at a stage subsequent to the multiplexer 902 that selects and outputs the output relating to the AD conversion circuit 801A, 801B as illustrated in FIG. 9, so as not to perform the correction when the angular frequency ωin of the input signal is ωs/4.
Assuming that the input signal into the time-interleaved ADC is cos(ωinnT+θ), the output signal y(n) from each of the AD conversion circuits 801A, 801B containing the skew (deviation in time) is expressed by the following Expression (7). When the gain of the AD conversion circuit 801A is G1 and the gain of the AD conversion circuit 801B is G2 in the Expression (7), G=(G1+G2)/2. Further, ωin is an input angular frequency, ωs is an operating angular frequency (sampling angular frequency) of the time-interleaved ADC, and T is an operation cycle of the time-interleaved ADC. Further, Δt is a skew (deviation in time), θ is an initial phase, and n is an integer equal to or larger than 0. The following Expression (7) is expanded utilizing cos((ωinΔt)/2)≈(ωinΔt)/2, sin((ωinΔt)/2)≈1 when Δt<<1.
                              [                      Math            .                                                              7                    ]                                                                                y                                                  (                  n                  )                                            =                                                                            G                                                                                cos                                                              (                                                                                ω                                                          i                                                                                n                                                                                nT                                                +                        θ                                            )                                                                                |                                      t                    =                                          nT                      +                                              Δ                                                                                t                          /                          2                                                                    -                                                                                (                                                          -                              1                                                        )                                                    n                                                                                (                                                      Δ                                                                                t                              /                              2                                                                                )                                                                                =                                                                            G                                                                                cos                                                              (                                                                                ω                                                          i                                                                                n                                                                                Δ                                                                                t                                                2                                            )                                                                                cos                                                              (                                                                                ω                                                          i                                                                                n                                                                                nT                                                +                                                                                ω                                                              i                                                                                n                                                                                Δ                                                                                t                                                    2                                                +                        θ                                            )                                                                      +                                                                                G                                                                                sin                                                        (                                                                                ω                                                      i                                                                                n                                                                                Δ                                                                                t                                            2                                        )                                                                  sin                                                  {                                                                                (                                                                              ω                                                          i                                                                                n                                                                                -                                                                                ω                              s                                                        2                                                                          )                                                                  nT                                        +                                                                                ω                                                      i                                                                                n                                                                                Δ                                                                                t                                            2                                        +                    θ                                    }                                                                                ≅                                                                                G                                                                                ω                                                      i                                                                                n                                                                                Δ                                                                                t                                            2                                                                                cos                                                                    (                                                                                ω                                                              i                                                                                n                                                                                nT                                                    +                                                                                ω                                                                  i                                                                                n                                                                                Δ                                                                                t                                                        2                                                    +                          θ                                                )                                                                                ︸                                          input                                                                                component                                                                      +                                                                                G                                                                                sin                                                        {                                                                                (                                                                                ω                                                              i                                                                                n                                                                                -                                                                                ω                                s                                                            2                                                                                )                                                                        nT                                            +                                                                                ω                                                          i                                                                                n                                                                                Δ                                                                                t                                                2                                            +                      θ                                        }                                                                    ︸                                      image                                                                                component                                                                                (        7        )
By multiplying the output signal y(n) by (−1)n by a multiplier 807 of the skew correction unit 803, a signal yc(n) expressed by the following Expression (8) is obtained.
                              [                      Math            .                                                              8                    ]                                                                                y                  c                                                                  (                  n                  )                                            =                                                                                (                                          -                      1                                        )                                    n                                                                  y                                                        (                    n                    )                                                                                =                                                                            cos                                                        (                                                                                ω                          s                                                                        nT                                            2                                        )                                                                                [                                                                                G                                                                                ω                                                                      i                                                                                n                                                                                Δ                                                                                t                                                            2                                                                                cos                                                                                (                                                                                ω                                                                              i                                                                                n                                                                                nT                                                                    +                                                                                ω                                                                                i                                                                                n                                                                                Δ                                                                                t                                                                        2                                                                    +                                  θ                                                                )                                                                                +                                                                                G                                                                                sin                                                                                {                                                                                (                                                                                ω                                                                              i                                                                                n                                                                                -                                                                                ω                                        s                                                                            2                                                                                )                                                                                nT                                                            +                                                                                ω                                                                          i                                                                                n                                                                                Δ                                                                                t                                                                2                                                            +                              θ                                                        }                                                                                ]                                                                                =                                                                                G                                                                                ω                                                  i                                                                                n                                                                                Δ                                                                                t                                        2                                                                          cos                                                              [                                                                                (                                                                                ω                                  s                                                                2                                                            -                                                              ω                                                                  i                                                                                n                                                                                )                                                                              nT                                                -                                                                                ω                                                              i                                                                                n                                                                                Δ                                                                                t                                                    2                                                -                        θ                                            ]                                                                      +                                                                                G                                                                                sin                                                        (                                                                                ω                                                      i                                                                                n                                                                                nT                                            +                                                                                ω                                                          i                                                                                n                                                                                Δ                                                                                t                                                2                                            +                      θ                                        )                                                                                (        8        )
Further, by shifting the signal yc(n) outputted from the multiplier 807 by π/2 by a phase shift circuit 808, a signal yd(n) expressed by the following Expression (9) is obtained.
                              [                      Math            .                                                              9                    ]                                                                                y                  d                                                                  (                  n                  )                                            =                                                                                G                                                                                ω                                                  i                                                                                n                                                                                Δ                                                                                t                                        2                                                                          cos                                                              [                                                                                (                                                                                ω                                  s                                                                2                                                            -                                                              ω                                                                  i                                                                                n                                                                                )                                                                              nT                                                -                                                                                ω                                                              i                                                                                n                                                                                Δ                                                                                t                                                    2                                                -                        θ                        -                                                  π                          2                                                                    ]                                                                      +                                                                                G                                                                                sin                                                        (                                                                                ω                                                      i                                                                                n                                                                                nT                                            +                                                                                ω                                                          i                                                                                n                                                                                Δ                                                                                t                                                2                                            +                      θ                      -                                              π                        2                                                              )                                                                                =                                                                                G                                                                                ω                                                  i                                                                                n                                                                                Δ                                                                                t                                        2                                                                          sin                                                              [                                                                                (                                                                                ω                                  s                                                                2                                                            -                                                              ω                                                                  i                                                                                n                                                                                )                                                                              nT                                                -                                                                                ω                                                              i                                                                                n                                                                                Δ                                                                                t                                                    2                                                -                        θ                                            ]                                                                      -                                                                                G                                                                                cos                                                        (                                                                                ω                                                      i                                                                                n                                                                                nT                                            +                                                                                ω                                                          i                                                                                n                                                                                Δ                                                                                t                                                2                                            +                      θ                                        )                                                                                (        9        )
Then, by multiplying the output signal y(n) by the signal yd(n) by a multiplier 809, an output expressed by the following Expression (10) is obtained.
                              [                      Math            .                                                              10                    ]                                                                                y                                      (              n              )                                ·                                    y              d                                                  (              n              )                                      =                                            {                                                                                G                                                                                ω                                                  i                                                                                n                                                                                Δ                                                                                t                                        2                                                                          cos                                                              [                                                                                ω                                                          i                                                                                n                                                                                nT                                                -                                                                                ω                                                              i                                                                                n                                                                                Δ                                                                                t                                                    2                                                -                        θ                                            ]                                                                      +                                  G                                                                                sin                                                              [                                                                                (                                                                                ω                                                                  i                                                                                n                                                                                -                                                                                ω                                  s                                                                2                                                                                )                                                                              nT                                                +                                                                                ω                                                              i                                                                                n                                                                                Δ                                                                                t                                                    2                                                +                        θ                                            ]                                                                                }                        ×                          {                                                                                G                                                                                ω                                                  i                                                                                n                                                                                Δ                                                                                t                                        2                                                                          sin                                                              [                                                                                (                                                                                ω                                  s                                                                2                                                            -                                                              ω                                                                  i                                                                                n                                                                                )                                                                              nT                                                -                                                                                ω                                                              i                                                                                n                                                                                Δ                                                                                t                                                    2                                                -                        θ                                            ]                                                                      -                                  G                                                                                cos                                                              (                                                                                ω                                                          i                                                                                n                                                                                nT                                                +                                                                                ω                                                              i                                                                                n                                                                                Δ                                                                                t                                                    2                                                +                        θ                                            )                                                                                }                                =                                                    1                2                                                                            (                                                            G                                                                                ω                                                  i                                                                                n                                                                                Δ                                                                                t                                        2                                    )                                2                                                          {                                                      sin                                                              (                                                                                ω                            s                                                                              nT                                                2                                            )                                                        -                                      sin                                                              [                                                                                (                                                                                2                                                                                ω                                                                      i                                                                                n                                                                                -                                                                                ω                                  s                                                                2                                                                                )                                                                              nT                                                +                                                                              ω                                                          i                                                                                n                                                                                Δ                                                                                t                                                +                                                  2                                                    θ                                                                    ]                                                                      }                                      -                                                                                G                    2                                                                          ω                                                                  i                                                                                n                                                                                Δ                                                                                t                                4                                                          {                                  1                  -                                      cos                                                              [                                                                                (                                                                                2                                                                                ω                                                                      i                                                                                n                                                                                -                                                              ω                                s                                                                                )                                                                              nT                                                +                                                                              ω                                                          i                                                                                n                                                                                Δ                                                                                t                                                +                                                  2                                                    θ                                                                    ]                                                                      }                                      -                                                                                G                    2                                                                          ω                                          i                                                                                n                                                                          Δ                                                                                t                                4                                                          {                                                      cos                                                              (                                                                        2                                                                                ω                                                          i                                                                                n                                                                                n                                                                                T                                                +                                                                              ω                                                          i                                                                                n                                                                                Δ                                                                                t                                                +                                                  2                                                    θ                                                                    )                                                        +                  1                                }                                      -                                                            G                  2                                2                                                          {                                                      sin                                                              [                                                                                (                                                                                2                                                                                ω                                                                      i                                                                                n                                                                                -                                                                                ω                                  s                                                                2                                                                                )                                                                              nT                                                +                                                                              ω                                                          i                                                                                n                                                                                Δ                                                                                t                                                +                                                  2                                                    θ                                                                    ]                                                        +                                      sin                                                              (                                              -                                                                                ω                              s                                                                                nT                                                    2                                                                    )                                                                      }                                                                        (        10        )
In the case where the angular frequency ωin of the input signal is not ¼ of the operating angular frequency ωs of the time-interleaved ADC, terms of the trigonometric function, when averaged, can be recognized to be 0 in Expression (10). Therefore, an output from an accumulative adder 810 that accumulatively adds the output y(n)·yd(n) from the multiplier 809 becomes as expressed in the following Expression (11). Using a detection value for skew correction, a coefficient generation unit 811 of the skew correction unit 803 generates a coefficient value using a detection value for skew correction and sets it in an adaptive filter 804 to thereby perform skew correction.
                              [                      Math            .                                                              11                    ]                                                                                y                                            (                n                )                                      ·                                          y                d                                                          (                n                )                                              _                =                                            -                                                                                G                      2                                        ·                                          ω                                              i                                                                                n                                                              ·                    Δ                                                                                t                                4                                      -                                                                                G                    2                                    ·                                      ω                                          i                                                                                n                                                        ·                  Δ                                                                                t                            4                                =                      -                                                                                G                    2                                    ·                                      ω                                          i                                                                                n                                                        ·                  Δ                                                                                t                            2                                                          (        11        )
On the other hand, in the case where the angular frequency ωin of the input signal is ¼ of the operating angular frequency ωs of the time-interleaved ADC, when ωin=ωs/4 is substituted into Expression (10), the output y(n)·yd(n) from the multiplier 809 becomes as expressed in the following Expression (12).
                              [                      Math            .                                                              12                    ]                                                                                y                                      (              n              )                                ·                                    y              d                                                  (              n              )                                      =                                            1              2                                                                  (                                                      G                                                                                ω                      s                                                            Δ                                                                                t                                    8                                )                            2                                                  {                                                sin                                                        (                                                                                ω                          s                                                                        nT                                            2                                        )                                                  -                                  sin                                                        (                                                                                ω                            s                                                                              Δ                                                                                t                                                4                                            +                                              2                                                θ                                                              )                                                              }                                -                                                                      G                  2                                                                  ω                  s                                                Δ                                                                                t                            16                                                  {                              1                -                                  cos                                                        (                                                                  -                                                                                ω                              s                                                                                nT                                                    2                                                                    +                                                                                ω                            s                                                                              Δ                                                                                t                                                4                                            +                                              2                                                θ                                                              )                                                              }                                -                                                                      G                  2                                                                  ω                  s                                                Δ                                                                                t                            16                                                  {                                                cos                                                        (                                                                                ω                            s                                                                              nT                                                2                                            +                                                                                ω                            s                                                                              Δ                                                                                t                                                4                                            +                                              2                                                θ                                                              )                                                  +                1                            }                                -                                                    G                2                            2                                                  {                                                sin                                                        (                                                                                ω                            s                                                                              Δ                                                                                t                                                4                                            +                                              2                                                θ                                                              )                                                  +                                  sin                                                        (                                          -                                                                                ω                            s                                                                              nT                                                2                                                              )                                                              }                                                          (        12        )
Through averaging by the accumulative adder 810, the detection value for skew correction becomes different from that in Expression (11) as illustrated in the following Expression (13).
                              [                      Math            .                                                              13                    ]                                                                                y                                            (                n                )                                      ·                                          y                d                                                          (                n                )                                              _                =                                            -                              1                2                                                                                (                                                      G                                                                                ω                      s                                                            Δ                                                                                t                                    8                                )                            2                                                  sin                                            (                                                                                ω                        s                                                                  Δ                                                                                t                                        4                                    +                                      2                                        θ                                                  )                                              -                                                    G                2                                                          ω                s                                          Δ                                                                                t                        8                    -                                                    G                2                            2                                                  sin                                            (                                                                                ω                        s                                                                  Δ                                                                                t                                        4                                    +                                      2                                        θ                                                  )                                                                        (        13        )
If the coefficient generation unit 811 of the skew correction unit 803 generates the coefficient value using the detection value for skew correction and sets it in the adaptive filter 804 to thereby perform skew correction, accurate error correction is not performed. Hence, a notch filter 806 that has a frequency characteristic as illustrated in FIG. 10 to reduce a component of ωs/4 is conventionally provided at a stage subsequent to the multiplexer 805 that selects and outputs the output relating to the AD conversion circuit 801A, 801B as illustrated in FIG. 8, so as not to perform the skew correction when the angular frequency ωin of the input signal is ωs/4.    [Patent Document 1] Japanese Laid-open Patent Publication No. 2013-191956    [Patent Document 2] Japanese Laid-open Patent Publication No. 2013-74308    [Patent Document 3] Japanese Laid-open Patent Publication No. 2013-31055    [Non-Patent Document 1] S. M. Jamal et al., "Calibration of Sample-Time Error in a Two-Channel Time-Interleaved Analog-to-Digital Converter," IEEE Trans. Circuits Syst. I, vol. 51, pp. 130-139, Jan. 2004
In the above-described conventional time-interleaved ADC, in the case where the angular frequency ωin of the input signal is ¼ of the operating angular frequency ωs of the time-interleaved ADC, the gain correction and the skew correction is not accurately performed. This is because when ωin*≠ωs/4, a component INPUT of the input signal and a component (image signal component) IMAGE of the error signal in the digital output signal become different frequency components as illustrated in FIG. 11A, whereas when ωin=ωs/4 the component INPUT of the input signal and the component (image signal component) IMAGE of the error signal in the digital output signal become the same frequency components as illustrated in FIG. 11B and is not distinguished from each other.

Analog-to-digital converter and semiconductor integrated circuit


A secondary battery including an electrode assembly; a can having an upper opening to receive the electrode assembly and having two facing wide walls, wherein the wide walls are asymmetrical to each other; and a cap assembly sealing the upper opening of the can.

1. Technical Field
Embodiments relate to a secondary battery. More particularly, embodiments relate to a secondary battery that can improve safety by controlling a short between electrode plates by using a can whose front and rear surfaces are asymmetrical to each other about a direction of a long edge and which may constantly reproduce a deformation shape when the battery is vertically compressed.
2. Description of the Related Art
A secondary battery may be manufactured by first forming an electrode assembly by winding cathode and anode plates and a separator interposed therebetween in a jelly-roll shape. Then, the electrode assembly may be disposed in a can with electrolyte. Finally, an upper opening of the can may be sealed with a cap assembly.
The can may have a roughly rectangular shape for a rectangular type secondary battery, and may be a metal container made of lightweight conductive metal, e.g., aluminum (Al) or aluminum alloy. Therefore, the can may function as a terminal in itself. The can may be formed by, e.g., deep drawing. All surfaces of the can may be formed to have the same thickness.
In a conventional secondary battery, the can may be deformed when physical impact is applied to both sides of the can about a vertical axis of the battery in a standard test, e.g., vertical compression, and accordingly the electrode assembly contained in the can may also be deformed. However, as described above, all surfaces of the can may have the same thickness; and thus it may be impossible to predict the deformation shape caused by an impact. In other words, it may be very difficult to obtain reproducibility of deformation because the can may be non-directionally deformed by, e.g., a vertical compression test or external impact. In addition, the electrode assembly in the can may also be exposed to irregular pressures. Accordingly, there is a problem that a short between electrode plates may occur at various positions to cause, e.g., fire, rupture, and/or explosion.