The impurity density of a photoelectric transducer n-layer (7) and the impurity density of a p-layer ( 6 ) of an impurity region in which the electric transducer (7) and a transfer channel (9) are formed, are each distributed to have its maximum value in a more interior part from the surface of a semiconductor substrate (5). Alternatively, i) a thin, high-density p-layer (34) and ii) a thick, low-density p-layer (33) of an impurity region in which the electric transducer (7) and the transfer channel (9 ) are formed may be formed. Each minimum potential in these two p-layers (33, 34) is made to have a different dependence on the voltage applied to an n-type semiconductor substrate ( 5). The thick, low-density p-layer ( 33 ) is formed in such a way that it comes into contact with part of the photoelectric transducer n-layer (7) at its bottom portion. The above constitution can bring about a solid-state image pickup device that can prevent the blooming phenomenon, causes less residual images, and can operate as an electronic shutter with ease.

1. Field of the Invention
This invention relates to a solid-state image pickup device, a process for manufacturing the device and a method of driving the device.
2. Description of the Prior Art
In recent years, solid-state image pickup devices making use of charge transfer systems as typified by a charge-coupled device (hereinafter "COD") have been markedly put into practical use in view of their low-noise characteristics.
A structure commonly used in a conventional solid-state image pickup device will be described below with reference to accompanying drawings.
FIG. 24 is a plan view of what is called a CCD type solid-state image pickup device. The solid-state image pickup device is comprised of a photoelectric transducer area 1, a vertical CCD transfer electrode area 2, a horizontal CCD transfer electrode area 3 and an output area 4.
Upon incidence of light emitted from an object on the photoelectric transducer area 1, electron-hole pairs are produced in the photoelectric transducer area 1 by the action of light. The electrons thus produced are sent from the photoelectric transducer area 1 to the vertical CCD transfer electrode area 2. Into the vertical CCD transfer electrode area 2, electrons of photoelectric transducer areas 1 arranged in the longitudinal direction of the vertical CCD transfer electrode area 2 are sent at the same time.
Then the electrons taken out to the vertical CCD transfer electrode area 2 are sent to the horizontal CCD transfer electrode area 3. Into the horizontal CCD transfer electrode area 3, electrons of vertical CCD transfer electrode areas 2 arranged perpendicularly to the longitudinal direction of the horizontal CCD transfer electrode area 3 are sent at the same time.
The electrons thus taken out to the horizontal CCD transfer electrode area 3 are outputted through the output area 4. Output signals thus obtained pass through an image reproducing circuit and are outputted as an image of the object from an output medium such as a display device.
FIG. 25 shows a cross section of the solid-state image pickup device along the line 25--25 (in FIG. 24) that passes across the photoelectric transducer areas 1 and the vertical CCD transfer electrode areas 2.
In the upper layer portion or main surface of an n-type substrate 5, a p-layer 6 having depth and density in given ranges is formed. A photoelectric transducer, an n-layer 7, is formed in a given region in the interior of the p-layer 6. A p-layer 8 with a high density is also formed in the p-layer 6 at a position spaced apart from the n-layer 7. An n-layer 9 that serves as a vertical CCD transfer channel is provided in the p-layer 8.
Signal charges accumulated in the n-layer 7 are read out to the n-layer 9 and then the signal charges are transferred within the n-layer 9 and in the direction perpendicular to the paper face of the drawing.
A high-density p-layer 10 formed on the n-layer 7 is formed so that any dark current caused by an interfacial level of Si-SiO.sub.2 can be prevented from occurring.
Across the p-layer 6 and a lower layer portion 5a (or a region where none of p-layers and n-layers are formed; hereinafter "substrate 5a") of the substrate 5, a reverse bias voltage Vsub that gives positive potential to the substrate and gives negative potential to the p-layer 6 is applied by means of an electric source 11. That is to say, the reverse bias voltage Vsub is applied across the p-layer 8 and the substrate 5a. Hence, the p-layer 6 located below the photoelectric transducer formed of the n-layer 7 becomes depleted. As a result of depletion of the p-layer 6, charges that have turned excessive with respect to the quantity of the charges that can be accumulated in the n-layer 7 are released to the substrate 5a side. It is designed to prevent the blooming phenomenon in this way.
Application of a pulse voltage to the n-type substrate 5 makes it also possible to release all the signal charges in the n-layer 7 to the substrate 5a side, that is to achieve the operation of what is called an electronic shutter.
An insulating film 12 comprising SiO.sub.2 or the like is formed on the surface of the substrate 5. On the insulating film 12, a vertical CCD transfer electrode 13 is formed above the p-layer 8 and n-layer 9 that constitute the vertical CCD transfer electrode area 2 and also above the region embracing a gap region between the n-layer 7 and the p-layer 8. The insulating film 12 is also formed on the side wall and upper surface of the transfer electrode 13 for the purpose of protecting the solid-state image pickup device from a physical impact or shock.
The vertical CCD transfer electrode 13 acts as an electrode for making the electrons accumulated in the n-layer 7 read out to the p-layer 8 or n-layer 9 that forms or serves as the vertical GCD transfer channel.
Thus, in order to prevent the blooming phenomenon or achieve the operation as an electronic shutter, the p-layer 6 must have density and depth in given ranges.
FIG. 26 shows impurity density distribution examined along the line 26--26 passing across the photoelectric transducer area 1 in FIG. 25.
FIG. 27 shows net values of the impurity densities shown in FIG. 26.
In both FIGS. 26 and 27, the impurity densities are plotted as ordinate, and the distance from the substrate surface is plotted as abscissa. The densities of p-type impurity atoms are indicated on the upper side of the ordinate and the densities of n-type impurity atoms are indicated on the lower side of the ordinate. Broken lines 14, 15, 16 and 17 in FIG. 26 represent the impurity densities of the p-layer 10, p-layer 6, substrate 5a and n-layer 7 in FIG. 25, respectively.
A solid line 18 in FIG. 27 represents the net values of the respective impurity densities shown in FIG. 26. The shaded region 19 corresponds to the net impurity density distribution of the photoelectric transducer n-layer 7, showing the amount of effective donors accumulated in the n-layer.
The impurity density 17 of the photoelectric transducer n-layer 7 is highest at the surface of the substrate 5. The density decreases with a depth toward the interior of the substrate 5. The p-layer 10 is formed at the upper part of the n-layer 7 so that the dark current can be decreased. The impurity density 14 of the p-layer 10 is higher than the density of the n-layer 7, and is less spread toward the interior of the substrate 5. Hence, the n-layer 7 comes to have the net impurity density 19.
The p-layer 6 has a low impurity density, but its impurity density is distributed in a broadly spread state. More specifically, its impurity density is at maximum at the surface of the substrate 5 and gradually decreases with a depth toward the interior of the substrate 5.
In the solid-state image pickup device, in order not to cause the blooming phenomenon, it is necessary for the photoelectric transducer n-layer 7 to be almost completely depleted after the electrons accumulated in the photoelectric transducer have been read out to the vertical CCD transfer electrode area. For this reason, the amount of the effective donors represented by the net impurity density 19 must be controlled to be an upper limit of the quantity of the charges that can be accumulated in the n-layer 7. In other words, it follows that the amount of effective donors determines an upper limit value of saturation characteristics of the photoelectric transducer.
The net impurity density 19 is a value obtained by subtracting the impurity density 14 of the p-layer 10 and the impurity density 15 of the p-layer 6 from a value obtained by adding the impurity density 16 of the substrate 5a to the impurity density 17. Because of the restrictions in view of each process, the net impurity density 19 depends on the impurity density 14 and impurity density 17. As to the impurity density 17, the density is highest at the surface of the substrate 5. The part where this density is highest is compensated by the impurity density 14 of the reverse conductivity type p-layer 10.
FIGS. 28 to 31 cross-sectionally illustrate a flow sheet for fabricating a conventional CCD type solid-state image pickup device.
In the main surface (i.e., the upper layer portion) of the n-type substrate 5, p-type impurity boron is ion-implanted. Thereafter, the p-layer 6 is formed by a high-temperature heat treatment. Thereafter, a resist pattern is formed by conventional photolithography on the region other than the region in which the vertical CCD transfer channel is formed. Using the resist pattern as a mask, boron is ion-implanted to form the p-layer 8. Thereafter, a resist pattern is again formed by conventional photolithography on the region other than the region in which the n-layer 9 in the p-layer 8 serving as the vertical CCD transfer channel is formed. Using the resist pattern as a mask, phosphorus is ion-implanted 2 to form the n-layer 9. Thereafter, the insulating film 12 is deposited on the main surface of the substrate 5 by thermal oxidation. An electrode material serving as the vertical CCD transfer electrode 13 is further formed on the insulating film 12 (FIG. 28).
Then, a resist pattern 20 is formed on the electrode material by photolithography on the region other than the region broader than the region that serves for the transfer electrode 13. Using the resist pattern as a mask, the electrode material is dry-etched until the insulating film 12 is uncovered. Next, using the resist pattern 20 as a mask and also making the insulating film 12 serve as a protective film, phosphorus is ion-implanted. The n-layer 7 serving as the photoelectric transducer is formed as a result of this ion implantation (FIGS. 29 to 30).
Thereafter, the resist pattern 20 is removed. On the surface of the substrate 5, an electrode material is formed with a region broader than the insulating film 12 and transfer electrode 13. Next, a resist pattern is formed on the region other than the region in which the transfer electrode 13 is formed. Using this resist pattern as a mask, the electrode material is dry-etched. Through the above process, the transfer electrode 13 is formed. At this time, the transfer electrode 13 must be provided also on the gap region between the n-layer 7, i.e., the photoelectric transducer from which electrons are read out to the vertical GOD transfer channel, and the p-layer 8. For this purpose, since in the dry etching carried out when the transfer electrode 13 is formed a side wall end of the n-layer 7 serving as the photoelectric transducer is originally on the same line with a side wall end of the transfer electrode 13, one side wall end of the transfer electrode 13 is shortened to be formed in the desired length (FIG. 30).
Next, using one end of this transfer electrode 13 and a resist as masks, boron is ion-implanted. The p-layer 10 for preventing dark current is thus formed on the n-layer 7 (FIG. 31).
The conventional solid-state image pickup device as described above has the following disadvantages.
The impurity density 17 is highest at the surface of the substrate 5, and this part where the density is highest is compensated by the impurity density 14 of the reverse conductivity type p-layer 10. Hence, of the impurity density 17 of the n-layer 7 introduced as a photoelectric transducer, the region having a relatively low density is used as the photoelectric transducer. In other words, a photoelectric transducer with a low density results in a small amount of the effective donors that can be accumulated there, and can not achieve the quantity of saturation charges at a sufficiently high level.
Accordingly, the impurities to lead into the region of impurity density 17 are implanted in an increased quantity. The implanted impurities are also diffused into the depth of the substrate by a high-temperature heat treatment so that the photoelectric transducer can have an increased area.
The high-temperature heat treatment, however, may result in a spread of the impurity density 17 in the direction perpendicular to the surface of the substrate 5. As a result, the impurities are also diffused in the gap region between the p-layer 8 and n-layer 7 and also in the p-layer 8, the vertical CCD transfer channel.
The positional relationship between an end portion of the n-layer 7 and the vertical CCD transfer electrode 13 is determined by the precision for the registration of the mask in the step of exposure carried out when the transfer electrode 13 is formed and also on the diffused region of the n-layer 7 formed by diffusion. For this reason, it is very difficult to control the position at which the n-layer 7 is formed by heat diffusion at a high temperature. A poor controllability for the positions of the end portion of the n-layer 7 and the vertical CCD transfer electrode 13 causes the electrons serving as signals to be left in the photoelectric transducer at the time of read-out where they are taken out from the photoelectric transducer to the vertical CCD transfer channel.
The electrons thus having been left cause the phenomenon of phantom or residual images, resulting in a serious deterioration of picture quality.
On the other hand, when the impurities are implanted in an increased quantity, faults in ion implantation increase to increase what is called white scratches. This results in a lowering of the yield.
Moreover, the p-layer 6 is formed as a single impurity layer. Hence the voltage applied to the p-layer 6 must be controlled in order to prevent the blooming phenomenon or achieve the operation as an electronic shutter.
In the device with such structure, the voltage applied to the n-type substrate 5 is usually controlled to be about 10 V in order to control the blooming phenomenon. A pulse voltage of about 30 V is also required in order to achieve the operation as an electronic shutter.
For the purpose of applying such voltages, the number of parts must be increased, resulting in an increase in power consumption, when camera-combined VTRs usually making use of the solid-state image pickup device are manufactured. This obstructs the manufacture of those being small-sized, lightweight and also of low power consumption.

Process for manufacturing a solid state image pickup device having increased charge storage and improved electronic shutter operation


A method and apparatus for reducing cross-talk in an oximeter. The oximeter includes a band pass filter. The amount of cross-talk through the band pass filter is estimated. Based on this estimate, the corner frequencies of the band pass filter are adjusted when it is designed to minimize the cross-talk. In one embodiment, a calibration mode is performed when a sensor is attached to the oximeter. In the calibration mode, the signals are measured with first only the red LED on and then with only the IR LED on. Any signal measured in the off channel is assumed to be a result of cross-talk from the other channel. The magnitude of the cross-talk is determined as a percentage, and subsequently the percentage is multiplied by the actual signal and subtracted from the other LED signal as cross-talk compensation.

The present invention relates to oximeters, and in particular to methods for reducing cross-talk between red and IR signals in pulse oximeters.
Pulse oximetry is typically used to measure various blood chemistry characteristics including, but not limited to, the blood-oxygen saturation of hemoglobin in arterial blood, the volume of individual blood pulsations supplying the tissue, and the rate of blood pulsations corresponding to each heartbeat of a patient. Measurement of these characteristics has been accomplished by use of a non-invasive sensor which scatters light through a portion of the patient's tissue where blood perfuses the tissue, and photoelectrically senses the absorption of light at various wavelengths in such tissue. The amount of light absorbed is then used to calculate the amount of blood constituent being measured.
The light scattered through the tissue is selected to be of one or more wavelengths that are absorbed by the blood in an amount representative of the amount of the blood constituent present in the blood. The amount of transmitted light scattered through the tissue will vary in accordance with the changing amount of blood constituent in the tissue and the related light absorption. For measuring blood oxygen level, such sensors have typically been provided with a light source that is adapted to generate light of at least two different wavelengths, and with photodetectors sensitive to both of those wavelengths, in accordance with known techniques for measuring blood oxygen saturation.
Known non-invasive sensors include devices that are secured to a portion of the body, such as a finger, an ear or the scalp. In animals and humans, the tissue of these body portions is perfused with blood and the tissue surface is readily accessible to the sensor.
A typical pulse oximeter will alternately illuminate the patient with red and infrared light to obtain two different detector signals. One of the issues with each signal, for the red and infrared (IR), is cross-talk. For example, the red signal, after filtering, will still be tailing off when the IR LED is turned on, and vice-versa. Typically pulse oximeter circuits include such filters to filter out noise before demodulating, such as the 50 or 60 Hz ambient light from fluorescent or other lights, or electrical interference. Such filtering can result in crosstalk when the filtering spreads out the red and IR pulses so they overlap.
One approach for dealing with cross-talk in the form of phase distortion, as opposed to the amplitude distortion the present invention addresses, is shown in U.S. Pat. No. 5,995,858. This patent shows an approach where the same signal drives the red and IR at opposite phases, giving a phase offset problem. This patent deals with a phase error in the response of the band pass filter of a reference signal causing cross-talk of red into IR and vice versa. In order to minimize or compensate for this phase error, the oximeter is operated with only the IR LED active, and then only with the red LED active. From this, a correction constant is determined that is used in the equation for determining oxygen saturation.


A safety web for retaining the lid of a waste drum during opening of the lid. Safety web 10 is adapted to form a secure containment volume 22 that prevents lid 14 from becoming an airborne safety hazard. Safety web 10 includes a belt 20 for securing the safety web to the drum. The ends of belt 20 are secured to a ratcheting turnbuckle 25 that allows adjustment of the length of belt 20. Safety web 10 further includes a plurality of radial straps 30 radially disposed about belt 20. The ends 32 of radial straps 30 are fixedly secured to belt 20. Radial straps 30 are further fixedly secured to each other at a central point 35 defined by the midpoint of each radial strap 30. An annular strap 40 is provided on safety web 10 between belt 20 and central point 35. In order to allow an operator to vent pressure off of the drum with safety web 10 in place on drum 12, a steel elongated pry bar 50 is also provided. Elongated pry bar 50 has a first end 55 adapted for grasping by the operator and a second end 60 adapted to engage the perimetric lip 62 of the drum lid so as to pry the lip 62 of the drum lid 14 upwards. A bend 65 and a short cross-member 70 cooperate to act as a fulcrum.

Hazardous wastes, such as chemical waste, biological waste, and/or radiological waste, are frequently stored in metal drums having a sealed lid. Typically, the lid has an annular recess that receives the upper edge of the drum and a ring is used to seal the lid to the drum. It is often necessary to remove the seal-ring and the lid for various reasons that can include adding additional waste or transferring the waste therein to another container. It is well known in the art that pressure can build up in the drum over time. Often this pressure can cause the sides of the drum to bulge, providing a ready indication of the pressure therein. However, frequently no outward sign of internal pressure is present. This pressure can present an extreme hazard to hazardous waste personnel that are manipulating the drums. For instance, the internal pressure is often sufficient to explosively propel the lid of the drum during opening of the drum. Unrestrained, the lid becomes a projectile, thus exposing nearby workers to potentially catastrophic injury.
Numerous methods of retaining various types of lid and covers can be found in the art. For instance, U.S. Pat. No. 2,493,225 issued to Cassidy on Jan. 3, 1950, for a device useful for sealing the lid on a glass canning jar. U.S. Pat. No. 2,984,511 issued to Hedrick on May 16, 1961, for a trash can cover lock which has a pair of extensible, resilient and flexible arms that are adapted to be connected to the receptacle handles and extend over the top of the lid, holding it firmly in place but enabling the owner to release the locking device when it is desired to access the receptacle. U.S. Pat. No. 3,140,79 which issued to Griffith, et al. Jul. 14, 1964, discloses a further retainer for a trash can lid that utilizes a coiled spring to secure the lid on the container. U.S. Pat. No. 4,095,830 issued to Spellman on Jun. 20, 1978 and discloses a T-shaped hold down device for securing the cover of a container and also maintains the container in an upright position. Spellman's hold down device comprises a resilient one-piece tension strap. U.S. Pat. No. 4,413,851, which issued to Ritter on Nov. 8, 1983, discloses an adjustable strap for holding the lid of a trash can, or similar receptacle, in a closed position.
What has been missing from the art is a universal fit web device that can be secured to a waste drum in such a manner as to provide a secure volume in which to raise the lid of the drum and that will retain the lid in the event that the lid is accelerated off of the drum by internal pressures. Additionally, what has been missing from the art is an elongated lever adapted to allow an operator to slowly pry the lip upwards so as to vent any internal pressure while the operator stands a safe distance away from the drum.
Accordingly, it is an object of the present invention to provide a safety web for retaining the lid of a waste drum within a secured volume thus preventing the lid from being explosively propelled off of the drum during opening of the drum.
A further object of the present invention is to provide a safety web for a waste drum that provides substantially universal fit and can be adjusted in size to be used on variety of different capacity drums.
Still another object of the present invention is to provide a web device that can be secured to a waste drum in such a manner as to provide a secure volume in which to raise the lid of the drum and that will retain the lid within the secure volume in the event that the lid is accelerated off of the drum by internal pressures.
Yet another object of the present invention is to provide an elongated lever adapted to be used in conjunction with the safety web and that is adapted to allow an operator to slowly pry the lip upwards so as to vent any internal pressure away from the operator while the operator stands a safe distance away from the drum.
Other objects and advantages over the prior art will become apparent to those skilled in the art upon reading the detailed description together with the drawings as described as follows.


Techniques to provide visualizations of possible malicious incidents associated with an event on a host device may include causing presentation of graphics of a process or thread in a user interface. Information about detected events may be transmitted to a computing device that generates the visualizations for presentation to an analyst to verify the malicious incidents. Based on patterns and information conveyed in the visualizations, the computer device or host device may take action to protect operation of the host device caused by the event.

With computer and Internet use forming an ever greater part of day to day life, security exploits and cyberattacks directed to stealing and destroying computer resources, data, and private information are becoming an increasing problem. Some attacks are carried out using "malware", or malicious software. "Malware" refers to a variety of forms of hostile or intrusive computer programs that, e.g., disrupt computer operations or access sensitive information stored on a computer (e.g., viruses, worms, Trojan horses, ransomware, rootkits, keyloggers, spyware, adware, or rogue security software). Malware is increasingly obfuscated or otherwise disguised in an effort to avoid detection by security software. Determining whether a program is malware or is exhibiting malicious behavior can thus be very time-consuming and resource-intensive.


A four-point link for the suspension of a rigid axle which has four bearing seats. Two bearing seats can be articulated on the axle and two can be articulated on the vehicle frame. The link has a single-piece link body which is inscribed by the trapezoid formed by the bearing seats. The link body is formed of a fiber-composite arrangement that comprises at least one longitudinal fiber arrangement. The longitudinal fiber arrangement encases the bearing seat, at least along half circumference thereof and extends along at least a portion of the link body in order to optimize loading, reduce mass and increase its application. Torsional compliance makes it possible to use relatively small and/or hard rubber bearings for articulating the four-point link or the vehicle axle.

Four-point links of the initially described type are known from the prior art and are used, in particular, in trucks and other utility vehicles. The four-point links of the type in question combine a number of functions and tasks in one component, for which a plurality of links or components in the region of the axle guide were previously required.
For example, the use of a four-point link eliminates the need, inter alia, for additional anti-roll bars for the anti-roll stabilization of the vehicle body, since the four-point link, together with the available trailing arms, can perform the task of guiding the axle in the transverse and longitudinal directions, and the task of providing torque support and anti-roll stabilization. The three-point links that are otherwise needed for axle guidance can also be omitted.
Proceeding therefrom, forged four-point links, which are created from multiple metal sheets or are designed as a cast part, are known from the prior art, for example from DE 195 21 874, DE 102 06 809, or DE 10 2004 014 610. In the case of the forging process, however, for reasons related to production, there is usually a massive rectangular cross-section for the arms of the four-point link, which results in heavy component weight and production costs that are too high, and, therefore, to increased fuel consumption and a reduced maximum load of the utility vehicle.
Assembled or welded and cast four-point links are also heavy and are expensive to produce. In the case of four-point links made of metal, in particular, the compliances required for an axle suspension are difficult to implement, which is why these must be implemented, to a large extent, by rubber bearing elements, which must be sized accordingly, having large volumes and different radial rigidities in different load directions. Due to the great deformations that occur as a result, these rubber bearings tend to wear, however, and may need to be replaced prematurely.


Despreading means 10 despreads a pilot signal included in a first received signal 1. Strength determination means 15 determines the strength of the despread pilot signal. Integration control means 16 determines the integration interval used by integration means 13, from the strength of the received pilot signal. The differences in strength detected by strength difference detection means 12 are added together by the integration means 13 over the period of time decided by the integration control means 16. The integration interval used by the integration means 13 is made changeable according to the receiving environment. Accordingly, when there is the superior receiving environment, there is reduced the load imposed on the integration means 13 when the integration means 13 performs the processing operations. Therefore, there can be realized a superior CDMA receiver phase tracking system which dissipates a fewer amount of electric power.

The present invention relates to a CDMA receiver phase tracking system, and more particularly, to a CDMA receiver phase tracking system which optimally changes the amount of processing operations for calculation of phase tracking according to the receiving environment, as well as to a CDMA receiver.
In code division multiple access (CDMA) spectrum spread digital communication, a pilot signal plays an important role in ensuring and maintaining synchronization between a base station and a mobile station. A CDMA receiver phase tracking system is used for ensuring synchronization with the pilot signal.
FIG. 4 shows the configuration of a conventional CDMA receiver phase tracking system. A signal 1 which is received by the CDMA receiver and converted into a signal of base band range through frequency conversion is input to despreading means 10, where the signal is despread. In short, voltage-controlled oscillation means 10a provided in the despreading means 10 produces a despread code. A despreading device 10b despreads a pilot signal contained in the received signal through use of the thus-produced despread code. Phase shift means 10c produces from the despread code a despread advance code whose timing is made faster by a given period of time and a despread lag code whose timing is made later by a given period of time. A changeover switch 10d permits alternate output of the despread advance code and the despread lag code. The despread timing signal is made earlier by a given period of time through use of the despread advance code, and the pilot signal included in the received signal is despread by the despreading device 10e. Further, despread timing is made later by a given period of time through use of the despread lag code, and the pilot signal included in the received signal is despread.
Strength determination means 11 determines the strength of the pilot signal despread by making the despread timing earlier by a given period of time or the strength of the pilot signal despread by making the despread timing later by a given period of time.
A strength difference detection section 12a provided in strength difference detection means 12 detects a difference between the strength of the pilot signal despread by making the despread timing earlier (or later) by a given period of time and the strength of the pilot signal despread by making the despread timing later (or earlier) by a given period of time, the strength of the latter pilot signal having been received from the strength determination means 11 and stored in a storage section 12 prior to determination of the strength of the former pilot signal. More specifically, a difference is detected by subtracting the strength of the pilot signal despread by making the despread timing later by a given period of time from the strength of the pilot signal despread by making the despread timing earlier by a given period of time.
Integral means 13A integrates a difference-between the pilot signal despread by making the despread timing by earlier a given period of time and the pilot signal despread by making the despread timing later by a given period of time-corresponding to the overall received data frame. On the basis of the result of integration, phase tracking control means 14 controls the despread timing of the despreading means 10.
However, in the foregoing existing CDMA receiver phase tracking system, the integration means 13 integrated the strength difference corresponding to the entire received data frame. It has already been known that an integration interval can be reduced in superior receiving conditions; namely, even if the strength difference corresponding to the entire received data frame is not integrated, there is obtained an accuracy of phase tracking which is identical with that obtained by integrating all the difference corresponding to the entire received data frame. However, the strength difference corresponding to the entire received data frame is integrated every interval on the basis of the assumption that the receiving environments will be deteriorated. For this reason, the tracking system has a problem of the integration means 13 performing excessive processing operations.
The present invention is aimed at solving the aforementioned problem in the existing system, and the object of the present invention is to provide a superior CDMA receiver phase tracking system in which there can be changed the interval at which the integration means 13 performs an integration operation according to receiving environments and which reduces the load imposed on the integration means by decreasing the amount of processing operations in a superior receiving environment, thus realizing low power consumption.
To solve the problem, the present invention provides a CDMA receiver phase tracking system having the following configuration. Specifically, despreading means despreads a pilot signal included in a received signal, and strength determination means determines the strength of the despread pilot signal. Integration control means decides an integration interval from the strength of the received pilot signal and by means of an ON/OFF switch activates or deactivates the integration means according to the integration time. Strength difference detection means detects differences in strength among received pilot signals having different phases, and the integration means adds together the strength differences, thus producing a received strength difference sum. Phase tracking control means adjusts a despread phase on the basis of the received strength difference sum.
With the foregoing configuration, the integration interval used by the integration means is made changeable according to receiving environments, and the amount of processing operations can be reduced in a superior receiving environment. Accordingly, the load imposed on the integration means can be reduced, thus enabling realization of reduced power consumption.
According to the first aspect of the present invention, a CDMA receiver comprises: despreading means which produces a first despread pilot signal by despreading at a first timing a pilot signal included in a received signal, produces a second despread pilot signal by despreading the pilot signal at a second timing earlier than the first timing by a given period of time, and produces a third despread pilot signal by despreading the pilot signal at third timing later than the first timing by a given period of time; first strength determination means which produces a first received pilot signal strength from the first despread pilot signal; second strength determination means which produces a second received pilot signal strength from the second despread pilot signal and a third received pilot signal strength from the third despread pilot signal; strength difference detection means for detecting a difference between the second received pilot signal strength and the third received pilot signal strength; integration means which adds together the strength differences and outputs a received strength difference sum; integration control means which determines an integration interval for the integration means from the first received pilot signal strength; an ON/OFF switch for activating or deactivating the integration means according to the integration interval; and phase tracking control means for adjusting the phase of the first timing on the basis of the received strength difference sum. The CDMA receiver changes the integration interval according to the strength of the received pilot signal, thus reducing the amount of integrating operations.
According to the second aspect of the present invention, the CDMA-receiver as mentioned above further comprises: demodulation means which demodulates the received data signal despread by the despreading means and outputs demodulated data; re-modulation means which modulates again the demodulated data and outputs re-modulated signal; error rate calculation means which calculates a receiving error rate from the received data signal and the re-modulated signal; and integration control means which decides the integration interval used by the integration means from the receiving error rate. The CDMA receiver reduces the integrating operations by changing the integration interval according to the receiving error rate calculated from the data signal and the re-modulated signal.
Further, according to the third aspect of the present invention, a CDMA receiver comprises: a receiving antenna for receiving a signal transmitted from a base station; a radio section which produces a base band signal by converting the frequency band of the received signal from a radio frequency range to a base band range; a despreading section which acquires received data addressed to the CDMA receiver by despreading the base band signal; a demodulation section which prepares demodulated data by demodulation of the received data; means for producing a phase tracking control signal from the received data and the demodulated data; and a phase tracking control section which determines the amount of processing operations for calculation of information regarding the phase of a pilot signal with reference to the phase tracking control signal and which controls the amount of processing operations required by the despreading section to perform phase tracking operations. The CDMA receiver reduces the amount of processing operations to be performed by the despreading section by controlling the amount of processing operations for calculation of information regarding the phase of the pilot signal, with reference to the phase tracking control signal calculated from the demodulated signal.
Furthermore, according to the fourth aspect of the present invention, a CDMA base station comprises: despreading means which produces a first despread pilot signal by despreading at a first timing a pilot signal included in a received signal, produces a second despread pilot signal by despreading the pilot signal at a second timing earlier than the first timing by a given period of time, and produces a third despread pilot signal by despreading the pilot signal at third timing later than the first timing by a given period of time; first strength determination means which produces a first received pilot signal strength from the first despread pilot signal; second strength determination means which produces a second received pilot signal strength from the second despread pilot signal and a third received pilot signal strength from the third despread pilot signal; strength difference detection means for detecting a difference between the second received pilot signal strength and the third received pilot signal strength; integration means which adds together the strength differences and outputs a received strength difference sum; integration control means which determines an integration interval for the integration means from the first received pilot signal strength; an ON/OFF switch for activating or deactivating the integration means according to the integration interval; and phase tracking control means for adjusting the phase of the first timing on the basis of the received strength difference sum. The CDMA base station changes the integration interval according to the strength of the received pilot signal, thus reducing the amount of integrating operations.
Moreover, according to the fifth aspect of the present invention, the CDMA base station as mentioned above further comprises: demodulation means which demodulates the received data signal despread by the despreading means and outputs demodulated data; re-modulation means which modulates again the demodulated data and outputs re-modulated signal; error rate calculation means which calculates a receiving error rate from the received data signal and the re-modulated signal; and integration control means which decides the integration interval used by the integration means from the receiving error rate. The CDMA base station reduces the integrating operations by changing the integration interval according to the receiving error rate calculated from the data signal and the re-modulated signal.
Still further, according to the sixth aspect of the present invention, a CDMA base station comprises: a receiving antenna for receiving a signal transmitted from a base station; a radio section which produces a base band signal by converting the frequency band of the received signal from a radio frequency range to a base band range; a despreading section which acquires received data addressed to the CDMA base station by despreading the base band signal; a demodulation section which prepares demodulated data by demodulation of the received data; means for producing a phase tracking control signal from the received data and the demodulated data; and a phase tracking control section which determines the amount of processing operations for calculation of information regarding the phase of a pilot signal with reference to the phase tracking control signal and which controls the amount of processing operations required by the despreading section to perform phase tracking operations. The CDMA base station reduces the amount of processing operations to be performed by the despreading section by controlling the amount of processing operations for calculation of information regarding the phase of the pilot signal, with reference to the phase tracking control signal calculated from the demodulated signal.
Still further, according to the seventh aspect of the present invention, a CDMA communications control method, wherein despreading means produces a first despread pilot signal by despreading at a first timing a pilot signal included in a received signal, produces a second despread pilot signal by despreading the pilot signal at a second timing earlier than the first timing by a given period of time, and produces a third despread pilot signal by despreading the pilot signal at third timing later than the first timing by a given period of time; first strength determination means produces a first received pilot signal strength from the first despread pilot signal; second strength determination means produces a second received pilot signal strength from the second despread pilot signal and a third received pilot signal strength from the third despread pilot signal; strength difference detection means detects a difference between the second received pilot signal strength and the third received pilot signal strength; integration means adds together the strength differences and outputs a received strength difference sum; integration control means determines an integration interval for the integration means from the first received pilot signal strength; an ON/OFF switch activates or deactivates the integration means according to the integration interval; and phase tracking control means adjusts the phase of the first timing on the basis of the received strength difference sum. The CDMA communications control method permits a change in the integration interval according to the strength of the received pilot signal, thus reducing the amount of integrating operations.
Still further, according to the eighth aspect of the present invention, the CDMA communications control method as mentioned above, in that demodulation means demodulating the received data signal despread by the despreading means and outputs demodulated data; re-modulation means modulating again the demodulated data and outputs re-modulated signal; error rate calculation means calculating a receiving error rate from the received data signal and the re-modulated signal; and integration control means deciding the integration interval used by the integration means from the receiving error rate. The CDMA communications control method reduces the integrating operations by changing the integration interval according to the receiving error rate calculated from the data signal and the re-modulated signal.
Still further, according to the present invention, a CDMA communications control method comprises: a receiving antenna for receiving a signal transmitted from a base station; a radio section which produces a base band signal by converting the frequency band of the received signal from a radio frequency range to a base band range; a despreading section which acquires received data addressed to the CDMA base station by despreading the base band signal; a demodulation section which prepares demodulated data by demodulation of the received data; means for producing a phase tracking. control signal from the received data and the demodulated data; and a phase tracking control section which determines the amount of processing operations for calculation of information regarding the phase of a pilot signal with reference to the phase tracking control signal and which controls the amount of processing operations required by the despreading section to perform phase tracking operations. The CDMA communications control method permits a reduction in the amount of processing operations to be performed by the despreading section by controlling the amount of processing operations for calculation of information regarding the phase of the pilot signal, with reference to the phase tracking control signal calculated from the demodulated signal.

Matsushita Electric Industrial Co., Ltd.


The present invention relates to a personalized service providing system and a profile information classifying and processing method thereof. The system, linked to a plurality of subscriber stations to provide a personalized service to a subscriber station, classifies and processes profile information for the service. In the profile information classifying and processing method, a) subscriber profile information is generated, b) the subscriber profile information is classified into static profile information and dynamic profile information, and c) the dynamic profile information is selected from the subscriber station to manage the selected dynamic profile information and the static profile information is selected from the system to manage the selected static profile information. The the static and dynamic profile information is classified into public and private profile information to manage the classified static and dynamic profile information.

(a) Field of the Invention
The present invention relates to an information classifying and service providing system, and more particularly, to a method for classifying and processing profile information and a personalized service providing system using the method.
(b) Description of the Related Art
In general, a customized service has been provided for a user when services based on available resources including predetermined contents are provided for the users through a network. The available resources are not randomly selected but are selected based on subscriber profile information to provide the customized service (i.e., a personalized service). Various methods for providing the personalized service have been studied, and in the methods, the service is generally formed based on the user profile information.
A prior art relating to the personalized service may be found in Korean Patent Publication No. 2003-0054104 entitled "Contents personalization method and apparatus by aggregating multiple profiles". In this patent, a profile is provided including information about user preferences, terminal content display, content display conditions, and content developer's requirements, a standard for generating personalized contents is automatically generated by matching the profile information according to a predetermined standard, and the personalized contents are generated according to the generated standard to be provided to a user terminal.
In the prior arts, the personalized service is provided by using the profile information and available resources without considering a subscriber environment which is varied in real time.
That is, the personalized service is provided in a centralized method using the profile information of users registered in a system without considering the subscriber environment which is dynamically varied according to a place and a time. In addition, when the profile information relating to the user is provided to the system, the system uses the provided profile information and available resources according to a subscriber location, and provides a customized personal service to the subscriber.
However, the profile information underpinning the personalized service may vary depending on the subscriber environment. Accordingly, an optimum personalized service may not be provided to the subscriber when the subscriber profile information previously provided to the system is used without considering the changing subscriber profile information.
Accordingly, it is required to efficiently classify and manage the subscriber profile information so as to provide the optimum personalized service.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

This patent is subject to a terminal disclaimer.

Personalized service providing system and profile information classifying and processing method thereof

Electronics and Telecommunications Research Institute


A semiconductor power device includes a device feature layer, a substrate contact layer and a voltage-sustaining layer between them. The voltage-sustaining layer includes alternating semiconductor and high permittivity dielectric regions, where each region extends from the device feature layer to the substrate contact layer. Due to the flux of charges transported dominantly through the dielectric regions, the whole voltage-sustaining layer behaves like a semiconductor having a much higher electric permittivity than that of the semiconductor itself, so that the field produced by the ionized impurities of the semiconductor regions can be much higher than that of the conventional one for sustaining the same reverse voltage, and the specific on-resistance can be lower than that of the conventional one. The use of high permittivity dielectric regions can also be applied to the charge-balance structure, i.e., to COOLMOST.

It is well known that in a conventional power device, the reverse voltage applied across an n+-region and a p+-region is sustained by a lightly doped thick semiconductor layer. Such a layer is called hereafter voltage-sustaining layer (VSL). As for a high-voltage power device, the specific on-resistance Ron (or the on-voltage) is also mainly determined by the voltage-sustaining layer, called as drift region in most cases. The lighter the doping of this layer is, and/or the thicker this layer is, the higher the breakdown voltage VB is, however, and the higher the on-resistance (or on-voltage) also is. In many power devices, one of the most important problems is to obtain both high breakdown voltage and low on-resistance. The relation between Ron and VB is an obstruction to make high performance power devices. Moreover, the above-mentioned Ron refers to the resistance per unit area of the conduction region in the voltage-sustaining layer, whereas actually, there are always some non-conduction regions in the voltage-sustaining layer. For instance, the region under the source-body region of a vertical-type (longitudinal-type) MOSFET and the region under the base electrode contact region of a bipolar transistor are both non-conduction regions.
The above problem was solved by the inventor (Chinese Patent No. ZL91101845.X, U.S. Pat. No. 5,216,275). The solution thereof is to utilize a composite buffer layer (or charge balance layer, shortly as CB-layer) between a p+-region and an n+-region to sustain voltage. The CB-layer contains two kinds of regions with opposite conduction type. These two kinds of regions are alternately arranged, as viewed from any cross-section parallel to the interface between the CB-layer and the n+ (or p+) region, whereas the previous VSL is always a semiconductor of single conduction type. The invention also discloses the MOST composed by the VSL. The on-resistance per unit area Ron is proportional to VB1.3. This represents a breakthrough to the conventional relation of VSL; meanwhile the other electrical performances of the MOST remain almost same.
Within the past few years, a significant change has taken place in the semiconductor power device industry. Through the use of structure of Super-Junction devices (i.e., structure of CB layer), COOLMOSTs have been capable of providing high voltage and high current.
FIGS. 1(a) and 1(b) illustrate a method of manufacturing a Super-Junction power device 1. The process begins with a semiconductor piece of a substrate 2 growing a first epitaxial layer 3. In the figures, the substrate 2 is a heavily doped n+ layer and the first epitaxial layer 3 is a lightly doped n layer. Ion implantation is performed to make a layer of p-type region 4 on layer 3. In general, an epitaxial layer is required for each 50 to 100 volts of sustaining voltage. Accordingly, as for a 600 volts transistor, it is required to sequentially deposit respective n-type epitaxial layers indicated by 5, 7, 9, 11 and 13 in FIG. 1(a). After each epitaxial layer is completed, it is required to make respective p-type ion implantation layer indicated by 4, 6, 8, 10, 12 and 14 in FIG. 1(a).
After the diffusion of p-type ion implantation layer 4, 6, 8, 10, 12 and 14, the p-region 16 is formed, and the region without influence of ion implantation is n-region 15 shown in FIG. 1(b). Thus the p-region and n-region with an arrangement are formed. The device layer, which is called device feature layer 17, is then performed. The device feature layer 17 includes n+ source region 18 formed by ion implantation, oxidation layer 19, and metal gate or polysilicon gate 20 thereon. There is a p+ region 21 between the two n+ source regions 18, below which there is a deep junction p+ region 22. The deep junction p+ region 22 connects to the p+ region 21.
Obviously, the above-mentioned manufacture method uses many times of epitaxy and it is very costly. Moreover, the CB-layer structure uses the principle of charge compensation, wherein the dose of dopants of p-regions and n-regions must be controlled precisely and this leads to increase of difficulty in manufacturing and increase of the cost of devices.
Another deficiency of the MOST with CB-layer structure is that, when the conduction current is very large, the electric charge of the carriers themselves affects the balance of the electric charge, which leads to a decrease of breakdown voltage with increasing of the current, i.e., a secondary breakdown phenomena. The safe-operating area (SOA) is therefore not very ideal.
Still another deficiency of the MOST with CB-layer structure is introduced by the two voltages existing between p-region and n-region, one of which is the built-in voltage, and the other is additional voltage produced by the on-resistance in a region when a current flows in the region. A depletion region existed between the two regions is caused by the two voltages, so that the area of effective section of the conduction region decreases. In other words, the on-resistance increases with the increasing of the current.

Super-junction voltage sustaining layer with alternating semiconductor and High-K dielectric regions


Techniques are disclosed for an adaptive and causal random linear network coding (AC-RLNC) with forward error correction (FEC) for a communication channel with delayed feedback. An example methodology implementing the techniques includes transmitting one or more coded packets in a communication channel, determining a channel behavior of the channel, and adaptively adjusting a transmission of a subsequent coded packet in the first channel based on the determined channel behavior. The communication channel may be a point-to-point communication channel between a sender and a receiver. The channel behavior may be determined based on feedback acknowledgements provided by the receiver. The subsequent coded packet may be a random linear combination of one or more information packets.

As is known in the art, some communication applications, such as streaming communication applications, require transmissions having low delays. There is, however, a trade-off between throughput and transmission delay which may prevent low delays from being achieved using very large data block lengths. Thus, classical approaches to information theory problems, which typically consider data block lengths to achieve desired communication rates (i.e. throughput), do not provide the desired trade-off between the throughput and the delay required for streaming communication applications.
Various forward error correction (FEC) techniques for packet-level coding have been proposed in attempts to address the problem of large in-order packet delivery delays. The challenges associated with packet-level coding are multifold due to a number of factors including, but not limited to, feedback, real-time delivery, and congestion characteristics. The challenge becomes even greater in the presence of round-trip time (RTT) fluctuations and variations in channel state (e.g. erasure bursts). When these factors are considered in conjunction with real-time transmission constraints, it becomes difficult to satisfy both a desired throughput and desired in-order delivery delay characteristics. This is particularly true in streaming communication applications requiring low transmission delays. Conventional techniques address only some of the challenges, such as reducing the in-order delivery delay to provide a desired reliability-delay trade off. Furthermore, the coding in such conventional techniques is, in general, performed in a deterministic manner, which deteriorates performance when a channel is bursty, an RTT fluctuates, or real-time transmission constraints are imposed.

Adaptive causal network coding with feedback


A substrate is transferred from an environment at about vacuum into a load lock through a first door. The substrate is then sealed within the load lock. The pressure within the load lock is raised to a high pressure above vacuum. A second door coupling the load lock to a high-pressure processing chamber is then opened and the substrate moved from the load lock into the high-pressure chamber. The substrate is then sealed within the high-pressure chamber. High-pressure processing, such as high pressure cleaning or high pressure deposition, is then performed on the substrate within the high-pressure chamber. Subsequently, the second door is opened and the substrate transferred into the load lock. The substrate is then sealed within the load lock. The pressure within the load lock is lowered to about vacuum and the first door opened. The substrate is then removed from the load lock into the environment.

1. Field of the Invention
The invention relates generally to semiconductor processing systems. In particular, the present invention relates to a load lock system for coupling a high-pressure processing module to existing semiconductor processing tools that operate at or near vacuum.
2. Description of Related Art
Semiconductor fabrication typically processes substrates, such as circular wafers, into semiconductor chips by sequentially exposing each substrate to a number of individual processes, such as photo masking, etching, implantation, and cleaning. Modern semiconductor processing systems often include cluster tools that aggregate multiple processing chambers around a central transfer chamber housing a substrate handling robot. The multiple processing chambers may include, for example, degas chambers, substrate pre-conditioning chambers, cool down chambers, transfer chambers, chemical vapor deposition (CVD) chambers, physical vapor deposition chambers, etch chambers, or the like.
The various processing chambers and the transfer chamber can be isolated from one another to limit potential contamination of the semiconductors and to ensure that optimal processing conditions are maintained. Examples of cluster tools can be found in U.S. Pat. Nos. 5,955,858, 5,447,409, 5,469,035, and 6,071,055, all of which are incorporated herein by reference.
Conventional processing performed in these processing chambers, such as Low Pressure Chemical Vapor Deposition (LPCVD), typically occurs at or near vacuum. Accordingly, a load lock is typically provided to introduce a substrate at atmospheric pressure into the cluster tool kept at vacuum
Semiconductor fabrication also typically requires cleaning resist and/or etching residue from the surface of the substrate. Generally, there are two methods for cleaning the surface of a substrate, namely, wet and dry processing. Wet processing consists of a series of steps of spraying and/or immersing the substrate in expensive chemical solutions that are typically not environmentally friendly. Instead, dry processing consists of a series of steps that use gasses instead of wet chemical solutions to clean the substrate. For example, ashing using an O2 plasma.
More recently, supercritical fluids, such as carbon dioxide (CO2) with or without co-solvents or surfactants, are now being used to clean or strip photoresists or post-etch residue from semiconductor substrates. Supercritical cleaning is, therefore, a cleaning process that is neither wet nor dry.
Cleaning with supercritical fluids is desirable, as such fluids retain the properties of a liquid, but have the diffusivity and viscosity of a gas. The solvency of supercritical fluids can be enhanced by the addition of chemical agents or co-solvents that interact with materials used in semiconductor manufacturing. The supercritical fluid, with or without a co-solvent, typically acts as a solvent to remove contaminants from the wafer surface and effectively clean the surface of the substrate.
Supercritical fluid cleaning technology can be applied in many industrial processes to significantly reduce or eliminate the use of hazardous chemicals, to conserve natural resources such as water, and to accomplish tasks previously not possible, such as rapid precision cleaning of small features (e.g., resist images, VLSI (Very Large Scale Integration) topographical features such as vias, etc.) of semiconductor devices.
Moreover, cycling pressure between high and low limits near the supercritical pressure and temperature may be practiced to achieve particular process performance. This is otherwise known as phase shifting.
Accordingly, supercritical fluid processing may be safer, less expensive, and more performance effective as compared to conventional wet or dry processing. However, unlike conventional processing, supercritical technologies require high-pressure working environments to maintain the supercritical fluid phase. Also, the effectiveness as a solvent of supercritical fluids is increased with increasing pressure.
Because of the large differences in working pressures, supercritical fluid cleaning is typically kept separate from conventional semiconductor processing. Therefore, when supercritical fluid processes are required, a substrate being processed in a cluster tool must first be removed from the cluster tool before being positioned in the supercritical fluid cleaning module. Thereafter, the substrate may need to be removed from the supercritical fluid cleaning module and repositioned in the cluster tool for further processing. This drastically decreases the overall throughput afforded by current automated cluster tool technology and increases the likelihood of contamination due to such transfers.
Coupling supercritical fluid cleaning modules to existing cluster tools has numerous challenges, including the large differences in pressures between the conventional processes and the supercritical fluid processes, the cycle time needed to pressurize and de-pressurize the process chamber, and contamination of the transfer chamber by particulates removed in the supercritical fluid cleaning module. Accordingly, a method and system for coupling a supercritical fluid cleaning module to existing automated processing tools would be highly desirable.

Load lock system for supercritical fluid cleaning


One embodiment of the present invention provides a system for mapping all possible paths between a source node and a destination node. During operation, the system receives a management frame, determines all possible next-hop nodes based on a destination address carried in the payload of the management frame. The system then selects one of the next-hop nodes, and modifies payload of the received management frame to include information associated with the next-hop nodes and the selected next-hop node. The system then forwards the modified data frame to the selected next-hop node.

1. Field
The present disclosure relates to network monitoring and troubleshooting. More specifically, the present disclosure relates to a system and method for detecting faults in data paths in a communication network.
2. Related Art
As more mission-critical applications are being implemented in data communication networks, high-availability operation is becoming progressively more important for network architects. It is often desirable to have a diagnostic tool that can detect and identify a failure point within the network. In the past, various types of mechanisms have been implemented to monitor, diagnose, and troubleshoot networks. For example, in a Fibre Channel (FC) network, an extended link services (ELS) frame, such as an Echo frame, can be used to test link connectivity. Similarly, in an Internet Protocol (IP) network, a host can "ping" another node to test the connectivity between these two nodes.
However, these current network diagnostic tools do not always meet the demands of a complex network. More specifically, when multiple paths exist between two nodes, the Echo or ping function cannot provide detailed information of all possible paths.

Path diagnosis in communication networks


An enclosed food processing device is provided having one or more conveyor belts and vertical agitators positioned above the belt. The agitators have forward and backward prongs that stir the food being processed without causing physical damage to it. The food enters the device through an inlet and is evenly distributed across a draining screen by an inlet deflector plate, which is adjustable to account for the different rates at which the food may flow into the device. Ramps are positioned under the device to collect liquid drained from the food, and the ramps have independent segments that separate the liquid based on the stage of the process at which it is drained from the food. A salting apparatus is provided for conveying salt to the food to be processed. The salt is dispensed in proportion to the amount of food to be salted. Salt is moved from a salt hopper into a chamber by a rotating dispensing wheel. The salting apparatus has a pump that moves a fluid, such as filtered air, through a Venturi pickup tee, where it creates a partial vacuum that pulls salt into the airstream from the chamber. The salt then is pushed through stationary salt distribution tubes and applied to the food to be salted.

The present invention is suitable for producing a variety of cheeses (designated herein as "stirred curd" cheeses), including American style cheeses, such as current manufacture, cheddar, Colby, American, and other washed curd varieties; Italian style cheeses, such as mozzarella, pizza cheese, Parmesan, Romano, and provolone cheeses; semi-soft cheeses, such as brick, Edam, Gouda, Muenster, Monterey Jack, and pepper jack; and Swiss varieties, such as traditional Swiss, baby Swiss, and Jarlsberg cheeses. It is suitable for salting any type of food product, including these and other types of cheeses. Cheesemakers have strong financial incentives to ensure that these cheeses are made up of uniform sized curds and have moisture levels that fall within specific ranges prescribed by government and industry bodies. In the United States, the United States Department of Agriculture (U.S.D.A.) prescribes the ranges for each type of cheese. The cheese moisture level is greatly affected by salt content and distribution.
For about the last twenty-five years, stirred curd cheeses have been produced in large, open, tub-like curd tables. Curd tables have vertical agitators mounted on an assembly above the table. As the assembly moves back and forth above the table, the cheese curds are mixed. The vertical agitators ensure that the curds, when mixed, are of uniform size. Thomson, U.S. Pat. No. 3,490,751, issued Jan. 20, 1970; Naulin, U.S. Pat. No. 1,499,026, issued Jun. 24, 1924; and McKinnon, U.S. Pat. No. 794,421, issued Jul. 11, 1905, disclose assemblies that stir cheese curds.
Curd tables have serious disadvantages, however. First, making stirred curd cheeses on a curd table is a labor-intensive process. The cheesemaker must start with an empty table, and then fill it with curds and whey. As the curds are mixed and processed, salt must be added to the curds by hand at the proper point in the processing. After mixing and processing the curds, the agitator attachments are removed and replaced with attachments that scoop the product from the table. Because the assembly can remove the product from the curd table only in small scoops, and cannot remove it all at once, the process of removing the curds is time consuming and labor-intensive. To make matters worse, because the assembly is not able to remove curds from the corners and edges of the curd table, after the assembly has been used to remove most of the curds the cheesemaker manually must remove the product that remains in the corners and edges of the curd table. Further, because some curds must sit for longer periods of time than others during the removal process, it is difficult to ensure that moisture levels are uniform in all of the curds. Specifically, because moisture is lost as the curds sit, the curds that are removed earlier will have a higher moisture content than those that are removed later.
In addition, the sequential nature of cheese curd processing on a curd table makes it difficult to obtain uniform salt concentrations and consistent levels of acid development. Bacteria are added to obtain the proper acid levels in the cheese; the acid develops at a rate that is a function of the amount of bacteria added and the time the bacteria are allowed to work. When the acid level is within the desired range, users of the curd table must spread salt over the curds manually. Because the salt is distributed by hand, uniform salt dispersion is inherently difficult; and because it takes several minutes to distribute salt over the curds, curds that are salted first are salted at an earlier stage of acid development than are those that are salted later. In addition, because it takes the cheesemaker several minutes to apply salt to the curds, the salt is not applied at a single point in the process. The result of these difficulties is that the acid development and moisture content of the curds are not uniform. Finally, this salting process also is labor-intensive, and inconsistent salt concentrations result because the quantity of cheese delivered from the vat to the curd table may vary from batch to batch.
Curd tables have other disadvantages, as well. Because the tables are open, the curds are exposed to airborne contaminants, the rate at which process heat is lost cannot be controlled, and moisture is lost into the atmosphere. Furthermore, the agitator assemblies are complex and require significant maintenance. In addition, curd tables drain the whey from the curds by means of a mesh screen at the bottom of the table. As the curds are mixed, however, they are pushed across the screen repeatedly, which effects a grating action on the curds. This grating action causes small particles, called curd fines, to be lost from the curds and pass through the screen, thus reducing yields.
When compared to curd tables, conveyor belt systems save labor. The belt systems that currently are in use were developed approximately fifteen years ago. They use horizontal agitators, which have sharp prongs that physically alter the curds by knitting them together and then grinding them up. Latimer et al., U.S. Pat. No. 4,538,510, issued Sep. 3, 1985, and Brockwell, U.S. Pat. No. 4,309,941, issued Jan. 12, 1982, disclose conveyor belt systems with horizontal agitators. Although systems with horizontal agitators are suitable for some types of cheeses, they are not suitable for processing stirred curd cheeses because they physically damage the cheese curds and cannot produce uniform sized cheese curds.
Horizontal agitator systems also have several inherent processing disadvantages. When the curds and whey are dispensed onto the conveyor belt, the mixture is of varying depths or thicknesses. Horizontal agitators are not able to level the mixture across the width of the belt, so mixing is not uniform. Furthermore, because the horizontal agitators tend to grind the cheese, they produce curd fines, thus reducing yields and causing profits to be lost. Also, because horizontal conveyor systems produce curds of different sizes, moisture content and salt penetration varies from curd to curd.
There also are disadvantages to the oscillating boom salting apparatuses currently used with conveyor belt systems. First, oscillating booms consist of many moving parts, and thus are expensive to manufacture and to maintain. More important for cheese processing purposes is that the booms apply more salt to the food at each end of the oscillation cycle, and thus do not apply salt to the curds in a uniform manner.
These salting problems are exacerbated by the use of the horizontal agitators with conveyor belts. Because the horizontal agitators cannot level the height of the curds across the width of the belt, the salt concentration varies based on the height of the curd mass where the salt is applied. Furthermore, horizontal agitators are unable to mix the salt uniformly across the width of the belt, and instead tend only to push the salt in the same straight-line direction in which the food already is travelling on the conveyor belt. In addition, horizontal agitators spin in a single location, so they are not effective for stirring the food.
Horizontal agitator systems also have sanitation problems. The bearings used with horizontal agitators are subject to large loads, and the bearings wear out and begin to leak. Conversely, cleaning materials may leak into and damage the bearings. Significant maintenance is required to detect and correct leakage problems as soon as they occur.
Neither the curd tables nor the conveyor belt systems provides a mechanism for monitoring the moisture level of the cheese curds. The moisture levels therefore cannot be measured until the next day. Because the moisture levels in fully processed cheese cannot be adjusted, if the moisture levels fall outside prescribed parameters, the entire previous day's production of cheese must be disposed of at less than fair market value for that type of cheese.
There is an unmet need for a food processing device that allows processing of large quantities of stirred curd cheeses while maintaining the physical consistency and integrity of the curds, and at the same time solves the timing problems associated with curd tables and reduces the amount of labor required to process the cheese curds. It further would be desirable if the food processing device had a mechanized salting apparatus that did not have moving parts, but that did spread the salt evenly over the food being processed and in proportion to the amount of food being processed.

Walker Stainless Equipment Company, Inc.


The present invention relates to the processes of racemization and deprotection of special N-protected amino acids in the acylase/racemase system for the total conversion of special N-protected racemic amino acids into optically pure amino acids.

1. Field of the Invention
The present invention relates to the processes of racemization and deprotection of special N-protected amino acids in the acylase/racemase system for the total conversion of special N-protected racemic amino acids into optically pure amino acids.
2. Discussion of Background
Optically pure enantiomers of both L- and D-amino acids are important starting compounds in chemical syntheses, as well as for parenteral nutrition. Many methods of producing oprtically pure amino acids are possible and known to a person skilled in the art. Suitable processes include relevant enzymatic processes since they take place catalytically and produce with very high enantiomer concentrations of amino acids.
A racemic mixture of amino acids is not optically pure and contains both L-amino acid and D-amino acid enantiomers. Both L-amino acid and D-amino acid enantiomers can be utilized through enzymatic catalysis of a racemic mixture of N-protected amino acids. For example, it is known that L-amino acids are prepared from a racemic mixture of N-acetylated amino acids by using amino acid acylases. However, it is thought that these acylases are specific only for the cleavage of N-acetyl-protected amino acids and amines/alcohols (EP99118844.2; A. S. Bommarius et al., Tetrahedron; Asymmetry, 1997, Vol. 8, 3197-3200). Further, various racemization processes have been developed to prepare L-amino acids from the remaining D-acetyl amino acid fraction of the racemic mixture. DE 19935268.2 discloses an acetylamino acid racemase in the acylase/acetylamino acid racemase system that can prepare optically pure L-methionine from a racemic mixture of N-acetylmethionine.
Less specific N-acetylamino acid racemases (AAR) have been described previously. These racemases can be found in the microorganisms Streptomyces atratus Y-53 (Tokuyama et al., Appl. Microbiol. Biotechnol. 1994, 40, 835-840) and Amycolatopis sp. TS-1-60 (Tokuyama et al., Appl. Microbiol. Biotechnol. 1995a, 42, 853-859). For example, the racemase of Amycolatopis sp. TS-1-60 can catalyze the racemization of N-carbamoylamino acids to L-amino acids, although with less than optimal activity.
Processes for complete conversion of amino acids other than acetyl-protected or carbamoyl-protected amino acids to optically enriched amino acids are not known. Further, racemases with the ability to convert amino acids other than acetyl-protected or carbamoyl-protected amino acids are not known. Therefore, there is a need for enzymatic processes that racemize N-protected amino acids in general, as well as those N-protected amino acids other than acetyl-protected or carbamoyl-protected amino acids. The N-protected amino acid products of such racemic converstions may then be converted into the optically enriched amino acid by a subsequent enzymatic cleavage of the protecting group(s).

Process for the production of amino acids


Various embodiments of the invention provide extend the switching frequency range of DC/DC multiphase switching regulators in order to overcome prior art frequency limitations in the number of available phases, for example, in low input to output ratio applications. In certain embodiments, this is accomplished by enabling partial overlap between multiple phases using asynchronous logic. The invention is easily scalable without introducing significant silicon area penalties.

A. Technical Field
The present invention relates to power supplies, and more particularly, to systems, devices, and methods of controlling DC/DC multi-phase constant on time switching regulators.
B. Background of the Invention
Multiphase DC/DC converters are used in consumer electronics applications to supply power to CPUs for notebook, servers, and in many other applications that require high DC/DC converter bandwidth, low inductor ripple current, reduced inductor size, reduced output capacitor decoupling requirements, and high output voltage accuracy when subjected to load current variations. Conventional constant on time architectures or adaptive on time architectures are not widely used for multiphase switching regulators with more than three phases, because compared to other solutions, these kinds of regulators suffer greatly from duty cycle limitations that disproportionally worsen as the number of phases is increased. At any given operating frequency, the duty cycle is limited by 1/Nph, where Nph represents the number of phases. The maximum duty cycle in existing applications is typically 25 percent, such that the maximum number of phases is three, which corresponds to a theoretical maximum duty cycle of 33 percent.
Conventional constant on time and adaptive on time multiphase DC/DC converters are typically implemented with single error amplifiers and single on time generators that generate non-overlapping consecutive phases. In fact, multi-phase architectures that use a single on time generator are incapable of generating overlapping phases for a constant load. Nonoverlapping consecutive phases are generated by blanking, in a present cycle, the on time pulse of the following cycle by a minimum off time that must expire before the on time pulse can be triggered. Unfortunately, the off time delay restriction may significantly slow down transient response time, especially for heavy load transients. In addition, the minimum off time reduces the theoretical maximum duty cycle limit of 1/Nph.
One possible approach to avoid the strict requirement of nonoverlapping multiple phases is to employ one error amplifier and one corresponding on time generator for each phase. However, using multiple error amplifiers greatly increases the complexity of the converter, for example, due to the difficulty to ensure proper phase shift between phases, which renders this approach rather impractical.
What is needed are tools for switching regulator designers to overcome the above-described limitations and to meet the new demands of the marketplace.

Systems and methods to control DC/DC multiphase switching regulators