Disclosed is a somatosensory recognition system for recognizing a human body's action and a recognition method thereof. The somatosensory recognition system comprises: an acquisition device configured to acquire a first motion track data of a body parts' action; a wearable device worn on the body parts and configured to acquire a second motion track data of the body parts' action; and a processing device configured to compare the first motion track data and the second motion track data and determine the body parts' action according to comparison result. The above somatosensory recognition system and the recognition method thereof can improve the accuracy of somatosensory recognition.

At present, with the progressive development of somatosensory recognition technology, somatosensory recognition has been applied in people's daily life more and more. Somatosensory recognition is mainly used to recognize and obtain a body's positions in movement, such as head, arms, or feet, and then implement man-machine control by means of auxiliary equipments depending on the data of the obtained positions. The somatosensory recognition may be applied in environment, such as in playing games, in control of TV set, and in the office. In case of TV somatosensory games as an example, people can play games easily while watching TV, and realize better man-machine interaction effect with the TV as a bearer.
However, in main stream somatosensory recognition systems, most of them capture body's action with image pick-up elements, and participators need to stand in just front of the image pick-up elements for capture an image accurately. However, there is certain error with the above-mentioned method. For example, while the body moves in three directions, i.e., Z (such as up-down direction relative to the image pick-up element), Y (such as left-right direction) and X (such as front-rear direction) directions, since the image pick-up element is not sensitive to the movement in Z direction, misjudgments tend to occur in the Z direction parallel to the image pick-up element. In particular in case of an arm as the recognized object, if the arm is blocked by the body, the conventional somatosensory recognition system can not acquire the arm's position, thereby failing to determine body's action accurately.

Somatosensory recognition system and recognition method thereof


Systems and methods consistent with the invention relate to the processing of invoices. According to one exemplary embodiment, a method for processing invoices associated with service contracts may comprise receiving data associated with a first service contract. The method may then analyze the first service contract data based on a processing rule. The method may then determine, based on the analyzed first contract data, whether the received first service contract data relates to an existing service contract. The method may then process an invoice associated with the first service contract based on the determination of whether the received first service contract data relates to an existing service contract.

Invoicing is an important if not indispensable part of today's business transactions. Generally speaking, an invoice is a commercial document issued by one business partner to another, evidencing a transaction in which terms such as the products or services, their quantities, and agreed prices are indicated. The issuance of the invoice from one business partner to another signifies that payment is due from the partner receiving the invoice (such as a customer) to the partner posting the invoice (such as a service provider) according to the agreed terms of the invoice. The invoice may also include references to prior documents, such as purchase orders, goods receipt, and other documents that have been produced in connection with the business transaction.
Businesses may use a customer relationship management (CRM) system to manage invoices for the business's customers. For instance, the CRM system may manage invoices for when a customer enters into a long-term contract for a particular service. If, however, the customer subsequently contracts for another service with the business, the CRM system may then generate a new business agreement with the customer, leading to a new invoice for that customer. The customer would thus receive multiple invoices from the same business partner.
Receiving multiple invoices from the same business partner can be burdensome for the customer. This problem is, of course, exacerbated as the customer contracts for more and more services, and thus receives more and more invoices. Current CRM systems, however, are not capable of generating a single invoice for a customer as they will generate a new contract account for each new service, causing the generation of the new invoice. Other customers may, however, want a separate invoice for each contracted service. Thus, a one-size fits all approach does not typically work for invoice processing.
Accordingly, there exists a need for an invoicing system that may efficiently process invoices in situations where, for example, a customer may contract for multiple services from a particular business.

Invoicing methods and systems for processing convergent contract accounts


An apparatus and method for shaping at least a portion of a medical balloon comprise a balloon shaping device capable of applying a radial inward force to at least a portion of the medical balloon and at least one vibratory device capable of applying vibratory energy to the at least a portion of the medical balloon.

Medical balloons are used in the body in a variety of applications including as dilatation devices for compressing plaque and for expanding prosthetic devices such as stents at a desired location in a bodily vessel. Because it is typically necessary for the balloon to traverse a tortuous anatomy as it is being delivered to the desired location in the bodily vessel, it is desirable for the balloon to assume as low a profile as possible.
One way to achieve a low profile is by folding the balloon to form a number of wings. Some examples of methods of forming wings on a balloon are described in U.S. Pat. Nos. 5,147,302 and 5,350,361. A common method employed to form wings on a balloon is to partially inflate a balloon and then impart an inward radial force about the periphery of the balloon using a plurality of members or "blades" which are distributed about the periphery of the balloon. As the blades move radially inward, wings are formed in the balloon.
When forming wings in balloons in this manner, however, special care must be taken to ensure that the blades do not have any sharp edges or burrs which would damage the balloon. To this end, some prior balloon folding apparatuses have blades that are equipped with a relatively soft tip of silicone or other material. However, providing the blade with a relatively soft tip may be insufficient to reduce the potential from damage to the balloon during wing formation. In addition to the above, as the tip of each blade pushes radially against the balloon, inconsistent frictional interface between each tip and the balloon material upon which they push may lead to the formation of wings having non-uniform lengths. Balloons having wings of non-uniform lengths may lead to a catheter having a larger profile when the wings are folded.
In prior folding techniques caution must be exercised to prevent the blades from applying damaging forces to the balloon and/or any structures underlying the balloon such as marker bands, bonds or hubs. Although the amount of force applied to the balloon may be reduced to avoid damaging the balloon and/or any underlying structures, sufficient force must, nevertheless, be applied to completely form the balloon wings so as to achieve the desired cross-section. Complete formation of the wing includes imparting one or more creases into each wing. The creases help the balloon to attain a reduced profile by providing wings that are relatively flat and thus are easily folded to provide the balloon with a reduced diameter. Prior methods that form the wings by closing the blades about the balloon may be insufficient to provide creases which are adequate.
In light of the above, it is a goal of the present invention to provide a wing forming method and apparatus that reduces the friction between the balloon and blades, provides for improved ability to produce wings having uniform lengths and/or provides for improved crease formation.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.

This patent is subject to a terminal disclaimer.

Balloon wing forming apparatus and method


A body limb movement limiter restrains the movement of a person's arm so as to protect the person's shoulder or restrains the movement of a person's lower leg with respect to the upper leg so as to protect the person's knee. The device uses a housing having a reel disposed therein with a tether attached thereto and a shear thickening non-Newtonian fluid disposed within the housing so that the fluid acts on the reel during a payout procedure of the tether. The housing is attached to a strap secured about the torso of the person while the free end of the tether is secured about the person's arm. Alternately, a pair of arms are pivotally secured to each other within a housing having the non-Newtonian fluid therein for limiting movement of one arm with respect to the other.

1. Field of the Invention
The present invention relates to a body limb movement limiter that uses a non-Newtonian fluid so as to prevent sudden rapid movement of a person's arm or leg, or other joint, thereby preventing injury to the person's injury-recovering joint.
2. Background of the Prior Art
In recovering from an injury to the shoulder, knee, or other joint, with or without surgery to the joint, slow and gradual use of the affected area is desired in order to build strength and prevent shortening of the affected tendon or ligament. If the joint is subjected to sudden rapid forces the healing process to the affected area can be compromised resulting in a slowing of the healing of the affected area, reinjury, or further damage to the affected area which can result in the need for additional medical intervention. This not only results in further discomfort to the patient but slows the overall healing and recovery time.
Devices have been proposed that help limit movement of a person's joint such as the shoulder, knee, elbow, ankle, hip, etc., so as to prevent the patient from subjecting the joint to sudden rapid acceleration and consequent forces on the affected area. Such devices help prevent the attendant damage that can result from such rapid acceleration and work with varying degrees of efficiency.
The problem with the movement limiting devices found in the art is that such devices, being linear in their deceleration capacity, limit the normal and desired movements of a user of such devices. Such devices fail to discriminate between a desired normal movement associated with the joint and an undesired rapid movement than can cause damage to the user. These devices tend to make many normal movements, such as walking or carrying groceries relatively uncomfortable. While such discomforts may be an acceptable tradeoff to some, for the benefit of minimizing damage resulting from undesired rapid acceleration, these discomforts are less than ideal.
Other prior art devices will allow normal movement associated with a shoulder or a knee to a point and once that point is surpassed, a braking action is applied. While these devices will prevent much of the damage associated with full rapid acceleration of the affected area, the sudden braking action can cause a jerking force on the shoulder or knee, which can result in undue discomfort or some amount of damage to the tendons or ligaments thereat.
Therefore, there exists a need in the art for a device that will prevent rapid movement associated with a person's shoulder or knee or other joint. Such a device will allow the user to perform normal desirable functions without undue discomfort, yet will prevent sudden rapid acceleration of a person's limb, resulting in pain, reinjury or damage to the person's joint. The deceleration provided by such a device must be gradual so as not to exert a jerking force onto the user's affected area. Ideally, such a device must be of relatively simple design and construction and must be relatively easy to don and use.


This automatic processing device for fabricating a sample piece from a sample by irradiating the sample with a charged particle beam is provided with: a structural information acquiring unit which acquires structural information indicating the structure of the sample before processing; a processing termination position acquiring unit which acquires termination position specifying information specifying a processing termination position corresponding to the structure of the sample; an image acquiring unit which acquires a processed surface image in which a processed surface appearing at the position at which the sample has been irradiated by the charged particle beam is captured; and a determining unit which determines whether the position of the processing by the charged particle beam has reached the termination position, on the basis of a comparison between the structural information acquired by the structural information acquiring unit and the processed surface image acquired by the image acquiring unit.

There have been known apparatuses that pick up a sample piece produced by irradiating a sample with a charged particle beam consisting of electrons or ions and then work the sample piece, into a shape that is suitable for various steps such as observation, analysis, measurement, etc. using a scanning electron microscope, a transmission electron microscope, or the like (refer to PTLs 1 and 2, for example).
For example, in case where a sample in which the same structural bodies such as memory devices are arranged so as to form repetitive structures is worked using a charged particle beam, a TEM analysis sample (TEM sample) may be produced while one certain structural body, for example, remains left. Where in this manner a sample is produced in the longitudinal direction of a long and narrow structural body or along the row of structural bodies arranged in a row, the scanning direction of a charged particle beam is corrected so that working can be performed in parallel with the structural body or the row. The same is true of not only production of a TEM sample but also all cases in which a cross section(s) is formed.


An image stabilization control circuit controls an optical element driving element configured to move an optical element provided in an imaging apparatus based on an output signal of a vibration detection element provided in the imaging apparatus. The image stabilization control circuit includes an analog-digital conversion circuit configured to receive an analog signal from a position detection element that detects the position of the optical element and convert the input analog signal into a digital signal, and a servo circuit configured to generate a correction signal for correcting the position of the optical element based on an output signal of the analog-digital conversion circuit and output the generated correction signal to the optical element driving element. The servo circuit includes a digital filter circuit and a register. The digital filter circuit performs filter processing based on a filter coefficient stored in the register.

1. Field of the Invention
The present invention relates to an image stabilization control circuit provided in an imaging apparatus (e.g., a digital still camera), which can prevent a captured image from being blurred when the imaging apparatus vibrates (camera shake).
2. Description of the Related Art
Recent imaging apparatuses, such as digital still cameras and digital video cameras, are equipped with a high-resolution image sensor having a large number of pixels and capable of capturing a high-quality image. However, if a user's hand holding an imaging apparatus vibrates in a shooting operation, a captured image is blurred. Therefore, to obtain a high-quality image, it is desired that an imaging apparatus has a camera-shake correction function.
More specifically, an imaging apparatus includes a detection element (e.g., gyro sensor) that detects an angular speed caused when the imaging apparatus vibrates. The imaging apparatus drives an optical element (e.g., a lens or an image sensor) according to a detected angular speed component so as to prevent a captured image from being blurred. Thus, even when the imaging apparatus vibrates, a captured still/moving image signal does not include any vibration component and therefore the imaging apparatus can obtain high-quality still/moving image signal free from blur.
FIG. 2 is a block diagram illustrating a conventional image stabilization control circuit 100 that has a camera-shake correction function. The image stabilization control circuit 100 is provided in an imaging apparatus and operates under the control of a main control circuit (not illustrated) provided in the imaging apparatus. The image stabilization control circuit 100 is connected to a position detection element 200, a lens driving element 300, and a vibration detection element 400.
The position detection element 200 detects the position of a lens provided in the imaging apparatus. For example, the position detection element 200 is a Hall element that generates induced current according to the absolute position of the lens and outputs a voltage signal.
The lens driving element 300 moves the lens according to a lens driving signal generated by the image stabilization control circuit 100. For example, the lens driving element 300 is a voice coil motor. The image stabilization control circuit 100 adjusts a voltage value applied to the lens driving element 300 (i.e., voice coil motor) and controls the position of a movable coil in the voice coil motor. In other words, the image stabilization control circuit 100 adjusts the position of the lens. The lens driving element 300 moves the lens on a plane perpendicular to an optical axis of the imaging apparatus.
The vibration detection element 400 detects vibration occurring in the imaging apparatus and outputs a detection signal to the image stabilization control circuit 100. For example, the vibration detection element 400 is a gyro sensor that can generate an angular speed signal corresponding to the vibration occurring in the imaging apparatus and outputs the generated angular speed signal to the image stabilization control circuit 100.
It is desired to provide at least two elements for each of the position detection element 200, the lens driving element 300, and the vibration detection element 400. Two or more elements corresponding to a horizontal component and a vertical component can be positioned on a plane perpendicular to the optical axis of the imaging apparatus for lens position detection, lens movement detection, and vibration detection of the imaging apparatus.
The image stabilization control circuit 100 includes a servo circuit 120, a lens driver 140, an analog-digital converter (ADC) 142, a central processing unit (CPU) 160, and a digital-analog converter (DAC) 162.
The servo circuit 120 generates a control signal supplied to the lens driving element 300 according to a voltage signal received from the position detection element 200. The servo circuit 120 includes an analog filter circuit associated with external electrical parts (e.g., a resistance element and a capacitor). The servo circuit 120 generates a control signal supplied to the lens driving element 300 so that the optical axis of the lens accords with the center of the image sensor provided in the imaging apparatus. The lens driver 140 generates a lens driving signal supplied to the lens driving element 300 based on an output signal of the servo circuit 120.
The ADC 142 receives an angular speed signal (an analog signal) from the vibration detection element 400 and converts the input analog signal into a digital signal. The CPU 160 receives an angular speed signal (a digital signal) from the ADC 142 and generates an angular signal indicating a movement amount of the imaging apparatus based on the input signal. The CPU 160 is connected to a memory (not illustrated) and performs angular signal generation processing based on a software program stored in the memory. The DAC 162 converts an angular signal (a digital signal) generated by the CPU 160 into an analog signal.
The servo circuit 120 generates a lens driving signal supplied to the lens driving element 300 based on a sum of an analog angular signal received from the DAC 162 and a voltage signal received from the position detection element 200. In other words, to eliminate any blur on an image caused by camera shake, the servo circuit 120 changes the position of the lens based on an angular signal indicating a movement amount of the imaging apparatus and enables the image sensor to capture an object image not including any blur. Thus, the imaging apparatus can obtain high-quality still/moving image signal while suppressing blur on a captured image caused by camera shake.
According to the conventional image stabilization control circuit 100 illustrated in FIG. 2, the servo circuit 120 includes an analog filter circuit. Therefore, the servo circuit 120 requires external electrical parts (e.g., an operational amplifier, a resistance element, and a capacitor). To change the control characteristics of the conventional image stabilization control circuit 100, it is generally necessary to adjust the filter coefficient of the servo circuit 120. However, the filter coefficient cannot be changed unless the associated external electrical parts are replaced. Thus, changing the filter coefficient is not easy.
A manufacturer of an imaging apparatus, if the imaging apparatus includes the above-described image stabilization control circuit 100, is required to frequently perform adjustment on filter coefficients of filter circuits that they develop and manufacture. The work efficiency significantly deteriorates when a manufacturer frequently replaces external parts to perform a filter coefficient adjustment. It is therefore desired that the filter coefficient can be easily changed.

Semiconductor Components Industries, LLC


Disclosed are methods for synchronizing the time basis of logged data between an implantable medical device such as an IPG and an external device. The IPG logs various operational parameters as data and associates the same with a possibly-inaccurate IPG time stamp and a sequence number. Periodically, the external device sends accurate true time data to the IPG, which, like the operational parameter data, is logged with an IPG time stamp and a next sequence number. The IPG then orders the data sequences and timing sequences by time stamp in a combined data log, and divides that data log into regions in accordance with reset conditions apparent in the time stamp data. Slopes indicative of the relation between true time and time stamps are calculated for various regions on an intra-region or inter-region basis, which then allows for true time estimates to be calculated for the data sequences, thus providing an accurate time basis for the logged data. The true time estimates for the data sequences may then be transmitted from the IPG to an external device for interpretation.

Implantable stimulation devices are devices that generate and deliver electrical stimuli to body nerves and tissues for the therapy of various biological disorders, such as pacemakers to treat cardiac arrhythmia, defibrillators to treat cardiac fibrillation, cochlear stimulators to treat deafness, retinal stimulators to treat blindness, muscle stimulators to produce coordinated limb movement, spinal cord stimulators to treat chronic pain, cortical and deep brain stimulators to treat motor and psychological disorders, and other neural stimulators to treat urinary incontinence, sleep apnea, shoulder sublaxation, etc. The description that follows will generally focus on the use of the invention within a Spinal Cord Stimulation (SCS) system, such as that disclosed in U.S. Pat. No. 6,516,227, which is incorporated herein by reference in its entirety. However, the present invention may find applicability in any implantable medical device system. For example, the disclosed invention can also be used with a Bion™ implantable stimulator, such as is shown in U.S. Patent Publication 2007/0097719, filed Nov. 3, 2005, which is also incorporated herein by reference in its entirety.
As shown in FIGS. 1A and 1B, a SCS system typically includes an Implantable Pulse Generator (IPG) 100, which includes a biocompatible case 30 formed of titanium for example. The case 30 typically holds the circuitry and power source or battery necessary for the IPG to function, although IPGs can also be powered via external RF energy and without a battery. The IPG 100 is coupled to electrodes 106 via one or more electrode leads (two such leads 102 and 104 are shown), such that the electrodes 106 form an electrode array 110. The electrodes 106 are carried on a flexible body 108, which also houses the individual signal wires 112 and 114 coupled to each electrode. In the illustrated embodiment, there are eight electrodes on lead 102, labeled E1-E8, and eight electrodes on lead 104, labeled E9-E16, although the number of leads and electrodes is application specific and therefore can vary.
As shown in FIG. 2, the IPG 100 typically includes an electronic substrate assembly 14 including a printed circuit board (PCB) 16, along with various electronic components 20, such as microprocessors, integrated circuits, and capacitors mounted to the PCB 16. Two coils are generally present in the IPG 100: a telemetry coil 13 used to transmit/receive data to/from an external controller 12 as explained further below; and a charging coil 18 for charging or recharging the IPG's power source or battery 26 using an external charger (not shown). The telemetry coil 13 can be mounted within the header connector 36 of the IPG 100 as shown.
As just noted, an external controller 12, such as a hand-held programmer or a clinician's programmer, is used to send data to and receive data from the IPG 100. For example, the external controller 12 can send programming data to the IPG 100 to dictate the therapy the IPG 100 will provide to the patient. Also, the external controller 12 can act as a receiver of data from the IPG 100, such as various data reporting on the IPG's status. The external controller 12, like the IPG 100, also contains a PCB 70 on which electronic components 72 are placed to control operation of the external controller 12. A user interface 74 similar to that used for a computer, cell phone, or other hand held electronic device, and including touchable buttons and a display for example, allows a patient or clinician to operate the external controller 12.
Wireless data transfer between the IPG 100 and the external controller 12 takes place via inductive coupling. To implement such functionality, both the IPG 100 and the external controller 12 have coils 13 and 17 respectively. Either coil can act as the transmitter or the receiver, thus allowing for two-way communication between the two devices. When data is to be sent from the external controller 12 to the IPG 100 for example, coil 17 is energized with alternating current (AC), which generates a magnetic field 29, which in turn induces a voltage in the IPG's telemetry coil 13. The generated magnetic field 29 is typically modulated using a communication protocol, such as a Frequency Shift Keying (FSK) protocol, which is well known in the art. The power used to energize the coil 17 can come from a battery 76, which like the IPG's battery 26 is preferably rechargeable, but power may also come from plugging the external controller 12 into a wall outlet plug (not shown), etc. The induced voltage in coil 13 can then be demodulated at the IPG 100 back into the telemetered data signals. To improve the magnetic flux density, and hence the efficiency of the data transfer, the IPG's telemetry coil 13 may be wrapped around a ferrite core 13′.
As is well known, inductive transmission of data from coil 17 to coil 13 can occur transcutaneously, i.e., through the patient's tissue 25, making it particular useful in a medical implantable device system. During the transmission of data, the coils 13 and 17 lie in planes that are preferably parallel. Such an orientation between the coils 13 and 17 will generally improve the coupling between them, but deviation from ideal orientations can still result in suitably reliable data transfer.
As mentioned previously, the IPG 100 can communicate various types of status data back to the external controller 12, such as the voltage of the battery 26 (Vbat) and other operational parameters of interest. Typically, such operational parameters are read and stored by the IPG 100 on a schedule, such as every ten minutes or so. Thereafter, the stored data may be communicated back to the external controller 12 at an appropriate opportunity (such as when the external controller 12 requests communication with the IPG 100), or may be queried by the IPG 100 for its own internal use as appropriate. Typically, such data is stored in a non-volatile memory, such as a flash EPROM memory, so that the data is preserved in the event that the IPG 100 looses power, such as when the battery 26 becomes depleted. Transfer of stored data back to the external controller 12 can allow the user or a clinician to interpret the stored data to some useful end, and such analysis may require connection between the external controller 12 and a computer (not shown).
Operational parameter data is also typically stored in the IPG 100 with a time stamp, which comprises the IPG's understanding of the time that particular data was logged. A time stamp usually comprises a numeric (e.g., binary) value determined by the IPG's internal timing circuitry. Such timing circuitry usually operates in conjunction with the IPG's clocking circuitry, and may be based upon a simple clock pulse counter to cite one simple example.
Unfortunately, the time stamp associated with the stored data can be unreliable for at least two reasons. First, the IPG's timing circuitry may be inherently inaccurate, such that the time stamps deviate from true time by an unacceptable margin. Second, and perhaps most significantly, loss of power in the IPG 100 can cause the timing circuitry to reset. For example, suppose the battery 26 in the IPG becomes so depleted that the IPG's timing circuitry can no longer operate. Although the battery 26 can be recharged and the timing circuitry later enabled, the timing circuitry will have lost its timing reference. Thus, after coming up from a reset condition, the IPG 100's timing circuitry would understand the IPG to be operating at "time zero," and would incorrectly start stamping logged data accordingly.
The inability to properly establish an accurate time basis for logged IPG data hampers the utility of such logged data, because certain logged data may only be useful when judged against an accurate time basis. To cite just one example, it may be important to assess battery voltage as a function of real time, because the rate of any degradation may be an important factor in determining when the IPG's battery 26 needs to be replaced (by explanting the IPG 100 from the patient). Without an accurate time basis, such battery voltage data, and other time-sensitive operational parameter data, may be of limited use.
Accordingly, it would be beneficial to improve the reliability of the time basis for data logged in an implantable medical device such as an IPG 100. This disclosure presents such solutions.

Methods and systems for improving the reliability of the time basis for data logged in an implantable medical device

Boston Scientific Neuromodulation Corporation


An inline inspection tool of this disclosure includes at least one sensor arm (50) having a sensor head (30) located at its distal end (51), the sensor head including an arched-shaped pipe contacting portion (33) between its forward and rearward ends (32, 34), the pipe contacting portion having a radius R and a width WC; and at least one triaxial sensor element (31) having at least a portion located directly below the arched-shaped pipe contacting portion and having a width WS, WC<WS. During the tool's travel through a pipeline, contact of the sensor head with the pipe wall lies along a single line of travel substantially equal to the width WC. Because of its shape, the sensor head better traces and maintains contact with the pipe wall to detect dents, wrinkles, weld intrusions, and other defects or anomalies in the pipe wall.

This disclosure is in the field of inline pipe inspection ("ILI") tools like those used to inspect oil and gas pipelines. More particularly, the disclosure relates to a triaxial sensor head of an ILI tool configured for use with flux leakage ILI technologies.
Inline pipe inspection tool customers are requiring improved identification and characterization of pipeline defects. In some cases, customers require multiple axis flux measurements as the implementation for accomplishing improved defect identification. This type of measurement can provide information that would be beneficial in defect identification.
In prior art ILI tools, multiple hall effect sensing axes has been achieved by using an array of single axis hall effect sensors. Single axis hall effect sensors have been available for decades and the tool platforms and data interpretation systems have been built around that technology. Use of an array of sensors has necessitated a rectangular or rectangular-shaped sensor head surface or contact face that contacts a comparatively large area of the pipe wall. See e.g. FIGS. 1 & 2.
Because of the large contact area, the rectangular head cannot track features such as dents and wrinkles in the pipe wall. Additionally, as the rectangular sensor head traverses weld intrusions, the head pulls away from the pipe wall until the entire length of the rectangular head clears the weld. The loss of inspection around these features of interest is not optimal.
Point contact arms have been used for deformation sensing, and there are point contact MFL arms that include uniaxial hall effect sensors. To date, no prior art ILI tool makes use of one or more triaxial hall effect sensors. in a head shape that tracks well along the pipe wall.

Single point contact triaxial sensor head for an inline inspection tool


Interference is a common problem in wireless communication networks. This disclosure provides a method and system that detect and locate interference sources based on various data describing or captured from an operational network during normal mobile wireless service times.

Modern wireless communications operate in interference limited environments where signal quality to and from network subscriber devices is limited in part by interference from other users served by the same or nearby cells. The design and optimization of these networks are based on having clear spectrum occupied only by radio frequency transmitting equipment associated with the specific network. However, this ideal of clear spectrum occupied only by intended users of the system is not always achieved.
Real world systems often experience unexpected network interference which may originate from intentional and or unintentional radio frequency (RF) generating sources. These potential interference sources include many things such as industrial machinery, electronics test equipment radiating signals in the bands of interest, undesired mixing products generated by the licensed system itself and illegal radio sources operating in the wrong frequency bands. The result of these system interference sources is degraded system service and reduced wireless network capacity coverage as the intentional system signals suffer capacity and quality losses due to these interferers.
Conventional approaches for detecting and subsequently locating these network interferers typically involve intentionally disabling transmitting equipment across large areas of the network coverage area and searching for interference sources using sensitive receiving equipment and directional antennas. These methods are very costly as they involve turning off the revenue-generating network equipment and deploying teams in the field, typically during maintenance windows, which are low network utilization times such as the middle of the night. If network interferers are only present outside of these search times, then they will not be detected or located as part of these searches.
Another approach to interference detection involves deployment & utilization of dedicated energy measurement probes throughout the serving areas. Energy detection probes in this context are radio receiving devices that quantify energy levels detected within defined radio frequency bands, as opposed to data level probes that detect information in RF transmissions. However, there are substantial costs associated with installing, maintaining and monitoring probes, and a large number of probes would be required to effectively cover network areas.

Method and system for detecting interference to wireless networks


A method of making a carbon nanotube bundle is provided. A plurality of carbon nanotubes is provided. A plurality of sulfur nanoparticles is disposed on the plurality of carbon nanotubes to form at least two visible carbon nanotubes. The at least two visible carbon nanotubes are stacked to form a carbon nanotube bundle preparation body. The plurality of sulfur nanoparticles in the carbon nanotube bundle preparation body is removed to obtain the carbon nanotube bundle.

A diameter of a carbon nanotube is only about 1 nanometer, and a length of the carbon nanotube may be about hundreds of nanometers to meters. In the related research process of carbon nanotube, carbon nanotube bundles with different diameters need to be prepared. However, because one single carbon nanotube is very thin, it can only be seen by scanning electron microscope, transmission electron microscope, atomic force microscope, scanning tunnel microscope, etc. Thus, it is not convenient for real-time imaging, and the imaging areas of the above mentioned devices are generally small. Furthermore, the above listed microscopes have strict requirements for detection conditions, it is difficult to spot transfer carbon nanotubes to form a carbon nanotube bundle. Although there are fewer requirements for the detection conditions of optical microscope, one single carbon nanotube is not visible under the optical microscope. A method to prepare a carbon nanotube bundle with a desired diameter under the optical microscope is desirable.


Aspects of the present disclosure describe techniques for controlling quantum states of ions in an ion chain for a quantum operation. For example, a method is described that includes providing, from a first direction, a global optical beam to the ions in the ion chain, and providing, from a second direction different from the first direction, to each ion in a subset of the ions in the ion chain, a respective addressing optical beam. The method further includes dynamically controlling each of the addressing optical beams being provided by using a respective channel in a multi-channel acousto-optic modulator (AOM) to implement, with the ion chain, one or more quantum gates in a sequence of quantum gates of the quantum operation. Aspects of a quantum information processing (QIP) system that includes the multi-channel AOM for performing the method are also described.

Aspects of the present disclosure relate generally to controlling the states of quantum bits (qubits) using counter-propagating optical beams.
Trapped atoms are one of the leading implementations for quantum information processing. Atomic-based qubits can be used as quantum memories, as quantum gates in quantum computers and simulators, and can act as nodes for quantum communication networks. Qubits based on trapped atomic ions enjoy a rare combination of attributes. For example, qubits based on trapped atomic ions have very good coherence properties, can be prepared and measured with nearly 100% efficiency, and are readily entangled with each other by modulating their Coulomb interaction with suitable external control fields such as optical or microwave fields. These attributes make atomic-based qubits attractive for extended quantum operations such as quantum computations or quantum simulations that could potentially have a long sequence of quantum circuits or quantum gates.
The accuracy of the states or the information in atomic-based qubits is important to avoid systematic errors that can accumulate during quantum operations and, therefore, it is desirable that techniques be developed to correct or adjust for these types of errors to reduce or eliminate their effects.

Multi-qubit control with acousto-optic modulators


Two files are configured for more rapid comparison by removing blank spaces from the code of all of the lines in each of the files to be compared and also by attaching a control to the beginning of each line of code in each of the two sources prior to be compared. After blank spaces are removed and the controls attached, the two files are compared to determine additions, deletions and changes. The program continues to compare the strings of identical length until all of the strings have been compared. By comparing only strings of identical length, the program is able to compare two sources in substantially less time than by using conventional means of comparison.

When comparing two sources of codes or text, the comparison process may be slow and inefficient, particularly when the files to be compared are very large. For example, some conventional comparison programs may take as much as sixteen hours to completely compare two sources. Therefore, a need exists for an apparatus and method which will reduce the time required to complete the comparison of two sources of code or text.

Apparatus and method for source compression and comparison

International Business Machines Corporation


A Finite Impulse Response (FIR) filter is implemented in software on a general purpose processor in a manner which reduces the number of memory accesses as compared to conventional methods. In particular, an efficient implementation for a general purpose processor having a substantial number of registers includes inner and outer loop code which together make

1. Field of the Invention
This invention relates to software implementations of discrete-time filters, and in particular to software implementations of a Finite Impulse Response (FIR) filter on a general purpose processor.
2. Description of the Relevant Art
Traditional implementations of discrete-time filters for signal processing applications have used a custom Digital Signal Processor (DSP) instruction to implement an N-tap filter. Such a DSP instruction is executed to perform a multiply-accumulate operation and to shift the delay line in a single cycle (assuming the delay line is entirely in zero-wait state memory or on-chip). For example, on a TI320C50 DSP, a finite impulse response (FIR) filter is implemented by successive evaluations of an MACD instruction, each evaluation computing an element, yn, of the filtered signal vector, i.e., of the output vector, y[K], such that:
                              y          n                =                              ∑                          i              =              0                                      N              -              1                                                                    h              i                                                  x                              n                -                i                                                                        (        1        )            where h[N] is the N-tap filter coefficient vector and x[K] is an input signal vector.
Unfortunately, for many portable device applications such as Personal Digital Assistants (PDAs), portable computers, and cellular phones, power consumption, battery life, and overall mass are important design figures of merit. In addition, very small part counts are desirable for extremely-small, low-cost consumer devices. Signal processing capabilities are desirable in many such portable device applications, for example to provide a modem or other communications interface, for speech recognition, etc. However, traditional DSP implementations of such signal processing capabilities create increased power demands, increase part counts, and because of the power consumption of a discrete DSP, typically require larger heavier batteries.

Abstract: K        [                            (                                                    L                1                            +                              L                2                                                                    L                1                                                          L                2                                              )                        N            +                        L          2                          L          1                    +      1        ]  memory accesses and KN multiply-accumulates, where L1 is the number of output vector elements computed during each pass through the outer loop and where L2 is the number of taps per output vector element computed during each pass through the inner loop. The efficient implementation exploits L1+2L2 general purpose registers. For an embodiment in which L1=L2=8, inner and outer loop code make

Abstract: K        (                  N        4            +      2        )  memory accesses, which for filter implementations with large numbers of taps, approaches a 4× reduction in the number of memory accesses as compared to conventional methods.


A cable system (10) has a plurality of CAUs (34) coupled to a variety of network devices (58-68) in the subscriber's premise (36). The network devices (58-68) transmit signals to the CAU (34) in a clear frequency (100). The signals are coupled to a filter (70) which blocks any ingress noise from the premise (36). The filter (70) is coupled to a mixer (76), which down converts the signals from the clear frequency (100) to a desired frequency (104). Upstream signals in a bypass band (102) are coupled from the network devices to a low pass filter (72). The signals are then combined with the downconverted signals and transmitted into the cable system (10).

Local communication networks are being designed for a wide variety of services, from telephony and broadcast television to set-top boxes, videophones and information services such as the internet. Providing these new services results in a new set of challenges to telephone and cable companies. Cable companies will have to design systems that can provide two way communication. While telephone companies will have to design a system which can simultaneously handle a variety of broadband signals.
Most likely these new services will all be provided through a single coaxial cable to the subscriber's premise. Inside the subscriber's premise a splitter will fan out a number of cable lines to the various devices needing connection to the cable system. The subscriber will be responsible for cabling within his premise, which will require a variety of splitters, connectors and couplers. Each splitter, connector and coupler is a potential source for ingress noise into the cable system. Any damage to the cable's shielding is another potential source for ingress noise.
Present, CATV systems have allocated the 5-42 MHz band for upstream signals (i.e., signals originating from the subscriber's premises). In this frequency band a wide variety of noise source exist. These include CB radios, low frequency police radios, and electromechanical devices, such as mixers. As a result, there exists an ingress noise concern for local communications networks providing a wide variety of interactive services.
One solution is to require high quality cabling within the user's premises. If all the connections were tight all the time and used high quality connectors and all unused terminals were terminated and there was no damage to the cables shielding, this would be an effective solution. However, traditionally the cabling within the subscriber's premise belongs to the subscriber and therefor it is difficult to monitor the quality and condition of the cabling.
A typical solution to noise problems in a communication system is to filter out the noise using frequency selective filters. However, this only works if the noise is in a different frequency band than the desired signal and in this case the likely noise sources are in the same frequency band as the desired signal. Thus there exists a need for a system and method to clear the desired frequency band of ingress noise before transmission of the desired signals.

Method and system for cleaning a frequency band


Toughened compositions from polyhydroxyalkanoate (PHA), preferably PHB reactively blended with maleated poly butadiene and with an epoxidized natural or synthetic rubber are described. The compositions preferably include clay nanoparticles which can be organically modified and can be exfoliated by the blend. The compositions can be used in a variety of applications, including automotive uses.

(1) Field of the Invention
Polyhydroxyalkanoates (PHAs), particularly polyhydroxybutyrate (PHB), are biodegradable polyesters derived from renewable resources and have shown excellent promise as environmentally friendly substitute for polypropylene (PP). This invention aims to reduce the inherent brittleness of PHA's (PHB), while retaining their attractive stiffness and strength, by incorporating functionalized (reactive) rubbers. This provides significant improvement in toughness with minimum compromise in the stiffness. Preferably clays are provided in the composites.
(2) Description of Related Art
Many semi-crystalline polymers like PHB, Nylon and PP exhibit very attractive strength and ductility at room temperature and under moderate rates of deformation. However, they become brittle under severe conditions of deformation such as low temperature or high strain rates, and can undergo a sharp ductile-to-brittle transition (Lu, et al., Journal of Applied Polymer Science, Vol. 76, 311-319 (2000)). In the brittle regime a crack can propagate with little resistance. Because of this poor performance at extreme conditions there has been considerable commercial and scientific interest in the toughening of semi-crystalline thermoplastics. An extensive literature is now available on the toughening of commodity as well as engineering polymers such as polyethylene (Bartzcak et al., Polymer, 40, 2331-2346 (1999); Bartzcak et al., Polymer, 40, 2347-2365 (1999); and Macromol. Mater. Eng. 289 360-367 (2004)), polyamide (D. M. Laura et al., Polymer 42, 6161-6172 (2001)), polypropylene (Ismail, H. and Suryadiansyah, Journal of Reinforced Plast. And Composites, 23, 6, 639-650 (2004); Van der Wal et al., Polymer, 39, 26, 6781-6787 (1998); and Van der Wal et al., Polymer, 40, 6031-6075 (1999)) and polyvinylchloride [Ishiaku et al., Journal of Applied Polymer Science, Vo. 73, 75-83 (1999); and Ishiaku et al., Journal of Applied Polymer Science, Vol. 69, 1357-1366 (1998)).
Under proper conditions and using appropriate compatibilizers, synergistic effects arise to create high impact toughened polyolefins (TPO). Typically, a stiff filler material is incorporated into this TPO matrix to overcome the lost stiffness and strength. These fillers were conventionally glass fibers (Mehta et al., Journal of Applied Polymer Science, Vol. 92, 928-936 (2004)) but recent developments and results (Okada, O., et al., Mater Res Soc. Symp Proc., 171, 45 (1990); Pinnavaia, T. J., et al., ACS Symp Ser 622, 250 (1996); Messersmith, P. B., et al., Chem Mater 6, 1719 (1994); Yano, K., et al., J. Poly Sci Part A: Polym Chem., 31, 2493 (1993); Vaia, R. A., et al., Chem Mater 5, 1694 (1993); Wang, Z., et al., Chem Mater 10, 3769 (1998); Ke, Y., et al., J. Appl Polym Sci 71, 1139 (1999); Hasegawa, N., et al., J. Appl. Polym. Sci. 63, 137 (1997); and Mohanty, A. K., et al., Proceedings of 9th Annual Global Plastics Environmental Conference (GPEC 2002), Feb. 26 & 27 (2003), Detroit Mich., Society of Plastics Engineers, Plastics Impact on the environment, Full paper published in the Proceedings 69-78, (2003)). Use of a nanoclay has been described in TPO's.
The incorporation of rubber particles into a brittle thermoplastic matrix is known to improve the impact properties and the toughness of the polymer (Amos, J. L., et al., U.S. Pat. No. 2,694,692 (1954); Baer, et al., U.S. Pat. No. 4,306,040 (1981); and Patel, P., et al., Rubber-toughened thermoplastics, Brit. Pat. (1978)). Under proper conditions and using appropriate compatibilizers, synergistic effects arise to create high impact toughened blends. But, adding low modulus rubber particles to the polymer lowers the stiffness and strength and this reduction in rigidity significantly lowers the scratch/mar resistance of the resulting blends. This problem has hindered the growth of rubber-toughened thermoplastics in the automotive industry. Hence, to overcome this brittleness, high modulus fillers like clay are incorporated into the toughened blend which, with optimal processing and chemistry, can regain this lost strength and stiffness (Suzuki, K., et al., Thermoplastic resin nanocomposites with good heat and impact resistance and rigidity for automobiles, Jpn. Kokai Tokyo Koho (2004); Ito, T., et al., Manufacture of polyolefin compositions for automobile parts with improved rigidity and heat resistance, Jpn. Kokai Tokkyo Koho (2004): and Maruyama, T., et al., Rubber nanocomposites containing layered clay minerals well dispersed therein, Jpn. Kokai Tokkyo Koho (2004)). General Motors and supplier partners recently launched a nanocomposite TPO-based step-assist which was the first instance of a nanocomposite material being used in automotive exterior applications (http://www.scprod.com/gm.html).
However PP and subsequently TPO are both non-biodegradable and also petroleum-based. Vast amounts and varieties of such plastics, notably polyolefins, are currently produced from fossil fuels, consumed and discarded into the environment, ending up as un-degradable wastes. Manufacturers are looking for alternative eco-friendly green materials that can replace these non-renewable-resource based non-biodegradable materials. Numerous recent federal acts and executive orders encourage the development of biobased products to assist in 'greening' the country through recycling and waste-prevention. These green biomaterials not only protect the environment and reduce greenhouse gasses but also increase national security by reducing dependency on foreign oil for our needs.
Another route to overcome the inherent brittleness of polyhydroxybutyrate is by using polyhydroxybutyrate-hydroxyvalerate (PHBV) copolymers, which have low levels of valerate. However, PHBV exhibits lower melting point than PHB and so narrows the utilization temperature range of the composition. PHBV is also costlier than PHB and this hinders its scope and usage.
U.S. Pat. No. 5,714,573 to Randall et al describes polylactide polymer compositions. The present invention does not use lactide polymers.
Based on the above literature, the following problems were identified with conventional toughened polymers:                1) The incorporation of rubber particles into a brittle thermoplastic matrix is known to improve the impact properties and the toughness of the PHA polymer but only under proper conditions and using compatiblizers.        2) Adding elastomer particles to the PHA polymer lowers stiffness and strength and this reduction in rigidity significantly lowers the scratch/mar resistance of the resulting blends.        3) Stiffness and strength of the PHA polymer can be regained by adding a stiff reinforcement like nanoclay but property improvements are only achieved if optimum dispersion and compatibility are created.        4) Clay is inherently hydrophilic and hence does not mix with the PHA polymer matrix. This leads to agglomeration and poor properties and this has to be overcome by modifying the clay surface.        5) Conventional TPO's are based on non-renewable resources and hence are not sustainable or ecofriendly and there is a need for alternative eco-friendly green materials that can replace these non-renewable-resource based non-biodegradable materials.        6) Performance limitations and high cost however have limited these PHA biopolymers to niche markets.        7) PHB is typically a bacterial biobased polymer. It has mechanical properties very similar to the matrix polymer PP in TPO. However, PHB's main drawbacks are its brittleness and thermal instability.

Methods of making nanocomposites and compositions of rubber toughened polyhydroxyalkanoates

Board of Trustees of Michigan State University


The average of two signed or unsigned integer numbers (A, B) rounded towards zero as prescribed in the MPEG standard is calculated in one instruction cycle by right shifting each of the operands by one bit position, summing the shifted operands, and incrementing the result as appropriate. The shifted operands are summed in an adder (302) that provides two versions of the average, one being the sum of the shifted operands and the other being the sum-plus-one of the shifted operands. A multiplexer (310) under control of a control circuit (308) selects one of the sum and sum-plus-one outputs. Incrementing (selecting the sum-plus-one output) is based on inspection of the shifted-out bits of the operands, the most significant bit of the sum, and a mode signal indicative of whether the operands are signed or unsigned values.

1. Field of the Invention
The present invention relates to calculating the average of two integer numbers, and more particularly to single instruction cycle calculation of the average of two signed or unsigned integer numbers with a correctly rounded result and without errors due to overflowing of intermediate results.
2. Description of Related Art
The Moving Picture Experts Group (MPEG) standard has emerged as the dominant standard for compressed digital video. The MPEG-1 standard specifies a compressed video bit-stream rate of approximately 1.5 megabits per second, and a compressed stereo audio bit-stream rate of approximately 250 kilobits per second. The second standard, MPEG-2, will specify compression rates for higher-bandwidth distribution media, and is in the process of being formalized. To meet the MPEG standard, video and audio compression and decompression products must rapidly process the various algorithms used to implement the MPEG standard.
The MPEG standards impose the need for bi-directional temporal differential pulse code modulation (DPCM) and half pixel motion estimation. FIG. 1 shows an illustrative block of pixels X. In practice, a block contains more pixels than shown in FIG. 1, which is abbreviated for clarity. For example, typically in video signal processing, the basic video information processing unit is a macro-block, which has a 16.times.16 pixel matrix comprising four 8.times.8 luminance blocks, and two 8.times.8 chrominance blocks. Each macro-block is part of a much larger luminance or chrominance frame, as the case may be. In FIG. 1, the pixel X represents either luminance or chrominance, with the output corresponding to an unsigned integer number.
MPEG motion processing involves half pixel motion estimation as well as full pixel motion estimation. In FIG. 1, the "H" points represent horizontal interpolations, the "V" points represent vertical interpolations, and the "Y" points represent both horizontal and vertical interpolations. The interpolations "H" and "V" are calculated in accordance with the expression EQU (X.sub.1 +X.sub.2)/2 (1)
wherein X.sub.1 and X.sub.2 are horizontally contiguous pixels for the interpolation "H" and are vertically contiguous pixels for the interpolation "V." The interpolations "Y" are calculated in accordance with the expression EQU (X.sub.1 +X.sub.2 +X.sub.3 +X.sub.4)/4 (2)
wherein X.sub.1 and X.sub.3 and X.sub.2 and X.sub.4 are diagonally contiguous pixels. In expressions (1) and (2), the symbol "/" as specified by the MPEG standard represents integer division with rounding towards zero. In round towards zero, all non-integers are rounded to the next smallest integer. That is, the integer component is left intact and the fractional component is truncated. For instance, 7/4 and -7/-4 are rounded to 1, and -7/4 and 7/-4 are rounded to -1.
The average of integer operands X.sub.1 and X.sub.2 has been implemented by summing the operands to obtain an intermediate result, and then right shifting the intermediate result by one bit in order to divide the intermediate result by two. While this is a simple operation, it does not necessarily lead to a properly rounded result in accordance with the MPEG standard. Furthermore, if intermediate result overflows before right-shift occurs then the result will not be properly rounded in accordance with the MPEG standard. Moreover, the operation may require a general purpose computer to execute several instruction cycles.
In calculation intensive applications such as MPEG motion processing, it is highly desirable to calculate the average of two integers rounded towards zero in a rapid and efficient manner.

Calculating the average of two integer numbers rounded towards zero in a single instruction cycle


Methods, apparatus and articles of manufacture for detecting illegitimate code generators are provided herein. A method includes generating a set of multiple verification algorithms; generating multiple versions of an authentication code associated with a protected resource, wherein each of the multiple versions of the authentication code satisfies all of the multiple verification algorithms; providing a first version of the authentication code from the multiple versions of the authentication code to a recipient, wherein the first version of the authentication code includes a first verification algorithm from the set of multiple verification algorithms; and providing a second version of the authentication code from the multiple versions of the authentication code to the recipient, wherein the second version of the authentication code includes (i) the first verification algorithm from the set of multiple verification algorithms and (ii) a second verification algorithm from the set of multiple verification algorithms.

Authentication codes (such as, for example, license codes (also referred to herein as serial numbers), voucher numbers, etc.) are commonly used for software and hardware activation. Fundamentally, the function of such code is as an authenticator, confirming that the user who enters the code has legitimate rights of access to the protected resource. An analogous use of such code can include functionality as a confirmation code, wherein a user purchases a product or service and enters the code, which confirms the purchase and/or the authority to access the product or service in question.
By way of example, traditional software activation licenses utilize a single algorithm which verifies that the license code is in the correct format. However, attackers wishing to facilitate unauthorized software use can reverse engineer this algorithm from the hardware or software implementation which embodies the algorithm, and produce an illegitimate license code generator (also referred to colloquially and herein as a "keygen") which can produce keys that are in the correct format.
Accordingly, keygens represent a significant problem for the use of software activation codes. Multiple existing approaches attempt to target this challenge. For example, one such approach includes online verification. In this approach, the vendor keeps a database of legitimately issued serial numbers, and the number entered for authentication and/or confirmation is checked against that database. However, this approach requires connectivity, which may not be available. Scenarios wherein connectivity may be at issue might include, for example, if the given software is designed to run in an offline environment, if the given software is intended to run in secure/air-gapped environments (such as in government classified networks), and/or the item being authenticated has to be done so early in the boot process that the network stack is not yet available.
Another existing approach includes the use of blacklists of serial numbers to curb serial number sharing. However, keygens can typically produce a multiplicity of serials which will not appear on a blacklist. Other existing approaches include the use of hardware authenticators. However, hardware authenticators, colloquially referred to as "dongles," pose high costs, both directly and operationally. In addition, many users resent the inconvenience of hardware authentications for software license verification.
Additionally, another existing approach includes the use of asymmetrical cryptographic algorithms, thus separating key generation (that is, using private keys) from key verification (that is, using public keys). However, with such an approach, the size of the resultant serial number is typically 50-100 characters long or more. Users have to be able to manually type and/or enter the resultant serial number, creating practicality and ease of use issues with such larger serial numbers. Further, an attacker may respond to an asymmetrical cryptographic algorithm by using a (version-specific) software patch to remove the algorithm (a technique that is also colloquially referred to as "cracking").
Accordingly, a need exists for effectively detecting keygens.


A monolithic white light emitting device is provided. An active layer in the monolithic white light emitting device is doped with silicon or rare earth metal that forms a sub-band. The number of active layers included in the monolithic white light emitting device is one or two. When two active layers are included in the monolithic white light emitting device, a cladding layer is interposed between the two active layers. According to this light emission structure, white light can be emitted by a semiconductor, so a phosphor is not necessary. The monolithic white light emitting device is easily manufactured at a low cost and applied to a wide range of fields compared with a conventional white light emitting device that needs a help of a phosphor.

Priority is claimed to Korean Patent Application No. 10-2004-0016473, filed on Mar. 11, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a white light emitting device, and more particularly, to a monolithic white light emitting device capable of spontaneous white light emission.
2. Description of the Related Art
Generally, white light emitting devices generate white light using light emission by a semiconductor and light emission by a phosphor (see U.S. Pat. Nos. 6,069,440 and 5,998,925). These light emitting devices absorb light emitted by the semiconductor using the phosphor, and together the phosphor and semiconductor emit light close to white in color. Specifically, the semiconductor usually emits blue light, and the phosphor absorbs the blue light emitted by the semiconductor to generate green/red light. Hence, the phosphor is a mixture of green and red fluorescent materials.
According to a hybrid white light emitting device having such a structure, it is not easy to implement an integrated circuit manufactured according to an existing semiconductor manufacturing process. Thus, a field to which the hybrid white light emitting device is applied is restricted.
T. Mukai has proposed a white light emitting device (LED) having no phosphors and using multi-band emission (see JJAP 41 (3A) L246 2002). Accordingly, Mukai's LED has a plurality of active layers to generate light of different wavelengths.
This LED, which is usually used in a backlight device, needs to be easily manufactured and to have high light-emission efficiency and whiteness to have wide commercial acceptance.


The waterproof and dustproof speaker system includes a base with four base sides defining a base internal space. The base internal space can accommodate various items. A passive acoustical radiator is mounted in two opposing sides. A lid is hinged to the base and includes lid sides defining a lid internal space and two speakers mounted in the lid. The lid also accommodates electronics for receiving audio program signals and driving the speakers. When the lid is closed onto the base, the internal space is sealed against the intrusion of water and dust. The waterproof speaker system is weighted and balanced so that waterproof speaker system floats upright in water with the lid uppermost.

With the advent of portable devices, such as smart phones, capable of storing large lists of music, a need exists for a portable speaker system that can produce quality sound reproduction. Furthermore, such a speaker system should be capable of functioning in environments in which water and/or dust are present.


A tape measure housing is comprised of two asymmetrical housing portions. The first housing portion comprises a receptacle in which the tape measure components are located. The second housing portion comprises a cover that encloses the first portion along a seam that is asymmetrically disposed on the assembled housing. The housing portions are weighted such that the center of gravity of the housing is oriented so that the housing will assume a predetermined orientation when dropped from a height.

The invention relates generally to tape measures and, more particularly, to an improved tape measure and housing.
It will be appreciated that tape measures typically comprise a tape wound on a reel that is rotatably supported in a housing. The tape may consist of a steel blade, a plastic or fiberglass ribbon or other relatively flexible material that can be wound on the reel. The tape has measurement indicia thereon such that it can be unwound from the reel and extended from the housing to measure linear distances. The tape may be rewound on the reel manually using a crank or automatically such as by using a spring. The exposed end of the tape typically includes an end hook for temporarily attaching the end of the tape to an article during use and for preventing the end of the tape from being wound all of the way into the housing.
As will be appreciated tape measures are often used in relatively harsh environments such as construction sites, industrial sites and other work sites. As a result tape measures are subject to impacts as a result of being dropped or otherwise struck. Most tape measure housings consist of a plastic or metal housing that comprises two substantially identical clam shell halves where the halves are joined together along a center line of the device and are secured together by screws, rivets or other fasteners. Existing tape measure housings are prone to failure as a result of being dropped or otherwise impacted because the tape measure housing is subjected to shear forces along the seam where the two housing halves are joined together that cause the connection between the housing halves to fail. As a result, the end user may be forced to prematurely replace the tape measure.
Thus, an improved tape measure and tape measure housing is desired.


Reduction of the amount of 1,1-diphenylethane formed in the production of ethylbenzene by alkylation of benzene with ethylene can be effected by alkylating at a low concentration of ethylene. This invention allows operation at a low molar ratio of phenyl groups per ethyl group and leads to a product containing less than 1.0 wt-% 1,1-diphenylethane relative to ethylbenzene. This invention is applicable to processes for the production of a wide variety of other commercially important alkylated aromatics.

Alkylation of aromatic compounds with a C.sub.2 to C.sub.4 olefin is a common reaction for producing monoalkyl aromatic compounds. An example of this reaction that is practiced industrially is the alkylation of benzene with ethylene to produce ethylbenzene. As is usual, several by-products accompany ethylbenzene production. A simplified summary of the alkylation reaction and its common product and by-products is given below: ##STR1##
Although the formation of the diethylbenzene and triethylbenzene isomers might, at first glance, be viewed as by-products that represent a reduction in the efficient utilization of ethylene, in fact each can be readily transalkylated by benzene to produce ethylbenzene, as shown below: ##STR2##
Combining alkylation and transalkylation can thus maximize ethylbenzene production. Such a combination can be carried out in a process having two reaction zones, one for alkylation and the other for transalkylation, or in a process having a single reaction zone in which alkylation and transalkylation both occur. In many cases, a single reaction zone is preferred over two reaction zones because of the savings in capital investment.
In contrast to diethylbenzene and triethylbenzene, 1,1-diphenylethane (1,1-DPE) can not be converted to ethylbenzene by alkylation, and thus 1,1-DPE represents a reduction in ethylene utilization efficiency and a loss of ethylene. In fact, the by-production of 1,1-DPE and of the heavier polyethylated benzenes other than diethylbenzene and triethylbenzene which are collectively referred to herein as heavies represents virtually all of the reduction in the ethylene utilization.
Although the ideal ethylbenzene process would form no 1,1-DPE, the current minimum requirement is that the amount of 1,1-DPE formed be not more than 1.0 wt-% of the alkylation reactor effluent relative to ethylbenzene. The formation of 1,1-DPE is assuming added importance and significance in view of the expectation in some areas of near-term minimum standards for the content of 1,1-DPE of not more than 0.5 wt-%.
It is useful to point out two key operating variables of ethylbenzene alkylation zones. The first key variable is the molar ratio of phenyl groups per ethyl group, which is often referred to herein as the phenyl/ethyl ratio. The numerator of this ratio is the number of moles of phenyl groups passing through the alkylation zone during a specified period of time. The number of moles of phenyl groups is the sum of all phenyl groups, regardless of the compound in which the phenyl group happens to be. For example, one mole of benzene, one mole of ethylbenzene, and one mole of diethylbenzene each contribute one mole of phenyl group to the sum of phenyl groups. The denominator of this ratio is the number of moles of ethyl groups passing through the alkylation zone during the same specified period of time. The number of moles ethyl groups is the sum of all ethyl and ethenyl groups, regardless of the compound in which the ethyl or ethenyl group happens to be. For example, one mole of ethylene and one mole of ethylbenzene each contribute one mole of ethyl group to the sum of ethyl groups, whereas one mole of diethylbenzene contributes two moles of ethyl groups.
The second key variable is the concentration of ethylene in the alkylation zone. A practical, mathematical approximation is that the concentration of ethylene depends on the molar ratio of phenyl groups per ethyl group according to the formula: EQU ethylene!.apprxeq.phenyl/ethyl ratio!.sup.-1.
Thus, increasing the phenyl/ethyl ratio decreases the concentration of ethylene.
It is known that a low concentration of ethylene or a high molar ratio of phenyl groups per ethyl group minimizes formation of 1,1-DPE. The amount of 1,1-DPE formed depends on the phenyl/ethyl ratio according to the formula: EQU 1,1-DPE!.apprxeq.phenyl/ethyl ratio!.sup.-2.
Thus, increasing the phenyl/ethyl ratio decreases the amount of 1,1-DPE formed. Although the decrease in 1,1-DPE formation that is conferred by a small increase in phenyl/ethyl ratio may be small, it also is very significant, resulting in a high phenyl/ethyl ratio being the condition of choice for minimizing 1,1-DPE formation. However, a high phenyl/ethyl ratio increases capital and operating costs that are usually associated with the recovery of excess benzene. These costs give impetus to a search for an ethylbenzene process that minimizes 1,1-DPE formation at a low phenyl/ethyl ratio.
In the prior art, this search for a commercially-viable ethylbenzene process that not only produces a small amount of 1,1-DPE but also operates at a low phenyl/ethyl ratio has not been fruitful. All of the prior art processes follow the same, well-known approach of dividing the alkylation zone into more and more catalyst beds and injecting smaller and smaller portions of the total ethylene into each bed. Where the allowed concentration of 1,1-DPE is relatively high, this approach undoubtedly confers some benefits. For example, if benzene is alkylated with ethylene in a single-bed alkylation zone that operates at a phenyl/ethyl molar ratio of 5, then the highest concentration of ethylene, which occurs at the point of ethylene injection is 16.7 mol-%. Downstream of the ethylene injection point, the ethylene concentration decreases to very low concentrations as the ethylene is consumed and ethylbenzene is formed, while the phenyl/ethyl ratio remains essentially the same. However, if the single bed is divided into four beds in series and if one-fourth of the required ethylene is injected into each bed, then the phenyl/ethyl ratio is 20 in the first bed, 10 in the second bed, 6.7 in the third bed, and 5 in the fourth bed. Accordingly, the highest concentration of ethylene is 4.8 mol-% in the first bed, 4.5 mol-% in the second bed, and 4.3 mol-% in the third bed, and 4.2 mol-% in the fourth bed. Thus, dividing the bed and splitting the ethylene injection increases the phenyl/ethyl ratio and decreases the highest ethylene concentration.
But, in order to operate at the low phenyl/ethyl ratios and to also attain the low concentrations of 1,1-DPE that are expected to become the minimum standard in the near future, this prior art approach is not viable. For example, if benzene is alkylated with ethylene in a four-bed alkylation zone that operates at an overall phenyl/ethyl molar ratio of 2 rather than 5 as in the previous example, then the phenyl/ethyl ratio ranges from 8 in the first bed to 2 in the fourth bed, and the highest ethylene concentration ranges from 11.1 mol-% in the first bed to 8.3 mol-% in the fourth bed. Compared to the previous example, the ethylene concentration in each bed approximately doubled, which would result in an unacceptable amount of 1,1-DPE formation. In order to reduce the ethylene concentrations to those in the previous example, the number of beds would have to be increased from 4 to 10, simply as a consequence of the fact that the overall phenyl/ethyl ratio had decreased from 5 to 2.
Thus, in response to industry's demand for lower phenyl/ethyl ratios and the market's demand for lower ethylene concentrations, the prior art process inexorably divides the alkylation reaction zone into a large number of very small catalyst beds. Because of a variety of technical, economic, and practical considerations, this inefficient solution by the prior art processes is unacceptable in the hydrocarbon processing industry.

Method for minimizing diarylalkane formation in alkylation of aromatics by olefins by zeolite beta


A photo detector circuit comprises a photodiode for detecting a reflected light beam from an optical recording medium and converting the light beam to a current output, and a current-voltage converter for converting the output current of the photodiode to a proportional voltage. In this circuit, the output current of the photodiode is inputted via a current mirror circuit to the current-voltage converter, so that the S/N is improved and the entire circuit can be formed into a single chip to thereby decrease the number of external elements with another advantage of dimensional reduction.

1. Field of the Invention
The present invention relates to a photo detector circuit for use in a photodiode amplifier or the like for amplifying and outputting a light signal received by a photodiode for example.
2. Description of the Related Art
In a reproducing apparatus or a reproducing section of a recording/reproducing apparatus adapted to play an optical disk or a magneto-optical disk for example, there is performed an operation of generating a reproduced RF signal or a servo error signal for execution of tracking servo or focus servo control, on the basis of a light signal derived from a reflected laser beam received by a photo detector of an optical pickup. Normally the signal received by such a photo detector is supplied, after being amplified, to a predetermined function circuit in the following stage.
FIG. 1 is a circuit diagram showing an exemplary photodiode amplifier circuit used to amplify a received light signal obtained by a photodiode which constitutes such a photo detector.
In this diagram, a photodiode PD1 serves as a photo detector, wherein its cathode is connected to a power supply line +Vcc, while its anode is connected to an inverting input of an operational amplifier OP1. It is supposed in this case that a stray capacitance C.sub.1 is existent between the inverting input of the operational amplifier OP1 and the ground.
The operational amplifier OP1 converts the output current (received light signal) i.sub.1 of the photodiode PD1 into a voltage proportional thereto and then amplifies the same. A resistor R.sub.1 is connected between the inverting input of the operational amplifier OP1 and an output terminal. A capacitance denoted by reference numeral C.sub.2 corresponds to a stray capacitance or a capacitor provided to flatten the frequency characteristic of the operational amplifier OP1 by suppressing the high-range peak in the frequency characteristic. Hereinafter the capacitance represented by C.sub.2 will be regarded as a stray capacitance.
In this diagram, an input equated noise v.sub.n1 to the operational amplifier OP1 is shown equivalently as it is inserted between a non-inverting input of the operational amplifier OP1 and the ground.
In the photodiode amplifier circuit of FIG. 1, when an output current i.sub.1 of the photodiode PD1 is obtained, the output voltage v.sub.1 of the operational amplifier OP1 is expressed as follows in a frequency range where the effects of stray capacitances C.sub.1 and C.sub.2 are merely slight. EQU v.sub.1 =-i.sub.1 .multidot.R.sub.1 +v.sub.n1 (1)
FIG. 2 shows a structural example of another photodiode amplifier circuit. The configuration of the photodiode amplifier circuit shown in this diagram is formed by modifying the photodiode amplifier circuit of FIG. 1 into AC coupling type. Since any circuit elements corresponding to those in FIG. 1 are denoted by like reference numerals or symbols, a repeated explanation thereof is omitted. The difference between the two circuits of FIGS. 1 and 2 resides in a portion enclosed with a one-dot chained line.
The configuration of the photodiode amplifier circuit shown in FIG. 2 is constituted by adding a resistor R.sub.2 and a DC blocking capacitor C.sub.3 to the circuit of FIG. 1. The resistor R.sub.2 is inserted between the anode of the photodiode PD1 and the ground, and the DC blocking capacitor C.sub.3 is inserted between the anode of the photodiode PD1 and the inverting input. In this case, therefore, only an AC component alone is supplied as the output current i.sub.1 of the photodiode PD1 to the inverting input of the operational amplifier OP.
In this case, if the resistor R.sub.2 and the DC blocking capacitor C.sub.3 are so set as to be sufficiently greater than the other resistor (R.sub.1) and capacitances (stray capacitances C.sub.1 and C.sub.2), then it follows therefrom that the output voltage v.sub.1 expressed by Eq. (1) can be obtained, in the predetermined signal band, from the operational amplifier OP1 as in the aforementioned photodiode amplifier circuit of FIG. 1.
In playing a magneto-optical disk for example, it is generally customary that, although a detailed explanation is omitted here, a differential detection output relative to the received light signals of two photo detectors is obtained for reproduction of RF signals by reading out from the disk the data recorded in the form of magnetic pits.
FIG. 3 is a circuit diagram of a photodiode amplifier circuit which is employable as a differential detector circuit to execute differential detection with respect to the received light signals of two photo detectors. Any circuit elements corresponding to those in FIG. 2 are denoted by like reference numerals or symbols, and a repeated explanation thereof is omitted.
In this case, the above-described two photo detectors correspond to photodiodes PD1 and PD11.
Since the amplifier circuit in FIG. 3 for amplifying the output current i.sub.1 of the photodiode PD1 is structurally the same as that of FIG. 2, any circuit elements corresponding to those in FIG. 2 are denoted by like reference numerals or symbols, and a repeated explanation thereof is omitted.
Meanwhile another amplifier circuit for amplifying the output current (received light signal) i.sub.11 of the photodiode PD11 comprises an operational amplifier OP1, resistors R.sub.11 and R.sub.12, stray capacitances C.sub.11 and C.sub.12, a DC blocking capacitor C.sub.13, and an input equated noise v.sub.n11. In this circuit, the connection of the component elements is the same as that in the amplifier circuit which comprises an operational amplifier OP1, resistors R.sub.1 and R.sub.2, stray capacitances C.sub.1 and C.sub.2, a DC blocking capacitor C.sub.3, and an input equated noise v.sub.n1 for amplifying the output current (received light signal) i.sub.1 of the photodiode PD1.
The output voltage v.sub.1 of the operational amplifier OP1 is supplied to an inverting input of a differential amplifier OP3, while the output voltage v.sub.11 of the operational amplifier OP11 is supplied to a non-inverting input of the differential amplifier OP3. The differential amplifier OP3 is supposed to have an amplification factor k.
In the above circuit configuration, the output voltage v.sub.1 of the operational amplifier OP1 becomes the same as the one expressed by Eq. (1) when the values of the resistors R.sub.2, R.sub.12 and the DC blocking capacitors C.sub.3, C.sub.13 are sufficiently greater than those of the other capacitors C and resistors R and in a frequency range where the influences of the stray capacitances C.sub.1, C.sub.2, C.sub.11, C.sub.12 are merely slight. Meanwhile the output voltage v.sub.11 of the operational amplifier OP11 is expressed as follows in accordance with Eq. (1). EQU v.sub.11 =-i.sub.11 .multidot.R.sub.11 +v.sub.n11 (2)
The differential amplifier OP3 produces its differential output voltage v.sub.0 which represents the difference between the output voltage v.sub.1 of the operational amplifier OP1 and the output voltage v.sub.11 of the operational amplifier OP11. This differential output voltage v.sub.0 is expressed as EQU v.sub.0 =k(v.sub.11 -v.sub.1) (3)
Supposing now that the circuit shown in FIG. 3 for example is a differential detection circuit of a photo detector adapted for a magneto-optical disk, it is considered that the resistors R.sub.1, R.sub.11, the amplification factor k and the output currents i.sub.1, i.sub.11 mutually have the following relationship. EQU R.sub.1 =R.sub.11 =R EQU k=1 EQU i.sub.1 =-i.sub.11 =i (4)
Further, input equated noises v.sub.n1 and v.sub.n11 from random generation sources can be simplified as EQU v.sub.n11 -v.sub.n1 =.sqroot.2v.sub.n (5)
Therefore, the differential output voltage v.sub.0 obtained from the differential amplifier OP3 in this case can be expressed as EQU v.sub.0 =2i.multidot.R+.sqroot.2v.sub.n (6)
In any of the photodiode amplifier circuits described above with reference to FIGS. 1 to 3, the received light signal of each photodiode is weak, and consequently a satisfactory S/N (signal-to-noise ratio) is required to ensure high-reliability data reproduction.
In case the input equated noise v.sub.n1 or v.sub.n11 to the operational amplifier is dominant over the S/N of the photodiode amplifier circuit, the S/N can be improved by increasing the value of the resistor R.sub.1 or R.sub.11 connected to the operational amplifier. However, since the output band width f.sub.z of the operational amplifier is decided as EQU f.sub.z =1/(2.sqroot..multidot.C.sub.2 .multidot.R.sub.1) (7)
there arises a problem that the band width is narrowed with an increase of the value of the resistor R.sub.1 or R.sub.11. Since the stray capacitance C.sub.2 acts to flatten the frequency characteristic, a limit is existent in decreasing the value thereof. Accordingly, improvement of the S/N by increasing the value of the resistor R.sub.1 or R.sub.11 to maintain a sufficient band width is somewhat restricted, and this means is not considered to be effective.
In order to solve the above problem, there is proposed, by the present applicant, a photodiode amplifier circuit having a configuration of FIG. 4, as exemplified in U.S. application Ser. No. 08/704721 filed on Jan. 31, 1996. The photodiode amplifier circuit of FIG. 4 also is structurally a differential detection circuit which performs differential detection with respect to received light signals of two photo detectors, similarly to the aforementioned amplifier circuit of FIG. 3. Any circuit elements corresponding to those in FIG. 3 are denoted by like reference numerals or symbols, and a repeated explanation thereof is omitted.
In the photodiode amplifier circuit of FIG. 4, a resistor R.sub.4 is inserted in series between a photodiode PD1 and a power supply line +Vcc, and similarly a resistor R.sub.14 is inserted in series between a photodiode PD11 and a power supply line +Vcc. Further a DC blocking capacitor C.sub.4 is inserted between a junction of the resistor R.sub.4 and the cathode of the photodiode PD1, and an inverting input of an operational amplifier OP11. Similarly, a DC blocking capacitor C.sub.14 is inserted between a junction of the resistor R.sub.14 and the cathode of the photodiode PD11, and an inverting input of an operational amplifier OP1.
In such a circuit configuration, output currents i.sub.1 and i.sub.1a, which are equal in quantity but opposite in phase to each other, can be obtained from the anode and cathode of the photodiode PD1. Similarly, output currents i.sub.11 and i.sub.11a, which are equal in quantity but opposite in phase to each other, can be obtained from the anode and cathode of the photodiode PD11.
When the values of the resistors R.sub.2, R.sub.12, R.sub.4, R.sub.14 and the DC blocking capacitors C.sub.3, C.sub.4, C.sub.13, C.sub.14 are sufficiently greater than those of the other capacitances C and resistors R and in a frequency range where the influences of the stray capacitances C.sub.1, C.sub.2, C.sub.11, C.sub.12 are merely slight, the output voltage v.sub.1 of the operational amplifier OP1 is obtained by amplifying, as expressed in Eq. (8) below, the current i.sub.2 produced through addition of the output currents i.sub.1 and i.sub.11a which are delivered respectively from the photodiodes PD1 and PD11 and have an in-phase relationship mutually. EQU v.sub.1 =-i.sub.2 .multidot.R.sub.1 +v.sub.n1 EQU i.sub.2 =i.sub.1 +i.sub.11a (8)
Similarly, the output voltage v.sub.11 of the operational amplifier OP11 is obtained by amplifying, as expressed in Eq. (9) below, the current i.sub..sub.12 produced through addition of the output currents i.sub.11 and i.sub.1a which are delivered from the photodiodes PD11 and PD1 respectively and have an in-phase relationship mutually. EQU v.sub.11 =-i.sub.12 .multidot.R.sub.11 +v.sub.n11 EQU i.sub.12 =i.sub.11 +i.sub.1a (9)
Further, the output voltage v.sub.0 of the differential amplifier OP3, to which the output voltages v.sub.1 and v.sub.11 of the operational amplifiers OP1 and OP11 are supplied, is expressed as EQU v.sub.0 =k(v.sub.11 -v.sub.1) (10)
Assuming th at the circuit shown in FIG. 4 is a differential detection circuit of photo detectors adapted for a magneto-optical disk, the resistors R.sub.1, R.sub.11, amplification factor k and output currents i.sub.11, i.sub.1a, i.sub.11, i.sub.11a can be simplified as EQU R.sub.1 =R.sub.11 =R EQU k=1 EQU i.sub.1 =-i.sub.1a =-i.sub.11 =i.sub.11a =i (11)
Further the input equated noises v.sub.n1 and v.sub.n11, which are random generation sources, can be simplified as Eq. (5) mentioned already. Therefore, the output voltage v.sub.0 of the differential amplifier OP3 in this case is expressed as EQU v.sub.0 =4i.multidot.R+.sqroot.2v.sub.n (12)
Comparing the output voltage v.sub.0 (Eq. (12)) of the differential amplifier OP3 in the photodiode amplifier circuit of FIG. 4 with the output voltage v.sub.0 (Eq. (6)) of the differential amplifier OP3 in the photodiode amplifier circuit of FIG. 3, the signal output obtained in the circuit of FIG. 4 is twice on condition that the noise components included in the output voltages v.sub.0 of the two differential amplifiers OP3 are equal to each other, so that the S/N is also improved twice as compared with the circuit of FIG. 3.
In manufacture of a photo detector, it is generally customary that, regarding a physical structure of semiconductor, at least cathodes of a predetermined number of photodiodes constituting a desired photo detector are formed to be mutually common.
However, in the photodiode amplifier circuit of FIG. 4 for example, the resistors R.sub.4 and R.sub.14 need to be connected respectively to the cathodes of the photodiodes PD1 and PD11, whereby at least two of the plural photodiodes of the photo detector corresponding to PD1 and PD11 should be so formed that the anodes and cathodes thereof are mutually independent.
Also in the photodiode amplifier circuit of FIG. 4, it is necessary to extract the received light signals, which are AC components, from the photodiodes PD1 and PD11 via the DC blocking capacitors C.sub.3, C.sub.13, C.sub.4, C.sub.14, so that the amplifier circuit configuration is limited only to an AC coupling type, and amplification of DC signal is impossible.
Further, in any of the photodiode amplifier circuits described heretofore, it is preferred that the whole structure be shaped into a single chip with dimensional reduction. However, since the capacitance values of the DC blocking capacitors C.sub.3, C.sub.4, C.sub.13, C.sub.14 and the resistance values of the resistors R.sub.2, R.sub.4, R.sub.12, R.sub.14 are great in the circuit of FIG. 4, it is difficult to construct the whole structure into a single chip inclusive of such component elements.

Photo detector circuit having a current mirror circuit


The application provides an antenna and a communications device, and pertains to the field of antenna technologies. The antenna includes a horizontally polarized antenna and a vertically polarized antenna that are disposed in a superposition manner. The horizontally polarized antenna includes a metal sheet, and the metal sheet can be separately connected to a double-sided parallel strip line in the horizontally polarized antenna and a first conductor of a coaxial cable. A diameter of a maximum inscribed circle of the metal sheet is greater than a line width of the double-sided parallel strip line, and both the metal sheet and the coaxial cable are located on a first side of a substrate. Therefore, the metal sheet can effectively suppress an induced current in the coaxial cable, and impact of the induced current on the vertically polarized antenna can be reduced.

In a wireless local area network (WLAN) service, to improve signal bandwidth of an access point (AP), more antennas may be integrated into the AP to increase a quantity of signal streams, and a combination of different polarized antennas may be used in the AP to reduce a channel correlation. For example, a horizontally polarized antenna and a vertically polarized antenna that are disposed in a superposition manner may be used in the AP.
A distance between the horizontally polarized antenna and the vertically polarized antenna is usually relatively short, to reduce a height of an antenna and implement low-profile design of the antenna.
However, because the horizontally polarized antenna is usually fed through a coaxial cable, an induced current is generated in a feeding process through the coaxial cable, and the induced current causes interference to signals received and transmitted by the vertically polarized antenna. In other words, isolation between the horizontally polarized antenna and the vertically polarized antenna is relatively low.