摘要:
A variable gain amplifier and offset cancellation loop circuit and methods for tracking and correcting DC offset errors that may vary in accordance with the gain of the variable gain amplifier. The circuit is designed to provide tracking of rapid changes in the offset error while maintaining a desired overall frequency response of the combined variable gain amplifier and offset loop. The offset loop cancellation circuit has a wide enough bandwidth to allow the offset cancellation loop to track rapid changes in offset errors that result from rapid changes to the amplifier's gain setting. A control circuit is provided to prevent the large offset cancellation loop bandwidth from having a detrimental effect on the amplifier's overall bandwidth when the amplifier is set to high levels of forward gain by adjusting the offset cancellation loop gain as the forward gain of the amplifier is altered.
摘要:
An electronic amplifier circuit that provides improved gain control linearity characteristics resulting from having a controllable field effect transistor (FET) acting as a degeneration resistance (degeneration resistance FET) and a controllable load resistance FET. The overall gain function of the amplifier exhibits improved linearity in part due to the presence of the load FET, which tends to cancel the nonlinear behavior emanating from the degeneration FET. The circuit also includes a control circuit for generating non-linear control signals that are responsive to process characteristics of the FETs, such that the degeneration resistance FET and load resistance FETs may be controlled more consistently and independently from process variations.
摘要:
An electronic amplifier circuit that provides improved gain control linearity characteristics resulting from having a controllable field effect transistor (FET) acting as a degeneration resistance (degeneration resistance FET) and a controllable load resistance FET. The overall gain function of the amplifier exhibits improved linearity in part due to the presence of the load FET, which tends to cancel the nonlinear behavior emanating from the degeneration FET. The circuit also includes a control circuit for generating non-linear control signals that are responsive to process characteristics of the FETs, such that the degeneration resistance FET and load resistance FETs may be controlled more consistently and independently from process variations.
摘要:
Methods and systems are provided for an improved phase detector utilizing analog-to-digital converter (ADC) components. In an embodiment, the method includes from an ADC having a sampling clock signal that determines sampling instants, obtaining a first comparison value between an analog signal and a first threshold voltage at a first sampling instant, and obtaining a second comparison value between the analog signal and a second threshold voltage at a second sampling instant. The method further includes, from a supplemental circuit, obtaining a third comparison value between the analog signal and a third threshold voltage at a third sampling instant between the first and second sampling instants. The method further includes processing the first, second, and third comparison values to determine a phase relationship between the analog signal and the sampling clock.
摘要:
A variable gain amplifier and offset cancellation loop circuit and methods for tracking and correcting DC offset errors that may vary in accordance with the gain of the variable gain amplifier. The circuit is designed to provide tracking of rapid changes in the offset error while maintaining a desired overall frequency response of the combined variable gain amplifier and offset loop. The offset loop cancellation circuit has a wide enough bandwidth to allow the offset cancellation loop to track rapid changes in offset errors that result from rapid changes to the amplifier's gain setting. A control circuit is provided to prevent the large offset cancellation loop bandwidth from having a detrimental effect on the amplifier's overall bandwidth when the amplifier is set to high levels of forward gain by adjusting the offset cancellation loop gain as the forward gain of the amplifier is altered.
摘要:
A peak detector circuit that responds rapidly to power transients, and yet is able to avoid interpreting data fluctuations as power transients by generating dual peak signals from an amplifier's differential output signal, where the dual peak signals have data ripple components that tend to cancel one another. The system and methods permit the peak detectors to be much more responsive to power transients by expanding their bandwith (shortening the time constants) to the point that low frequency data components affect the individual peak detector signals, but the effects are cancelled out when the individual components are added together. The peak detector described herein may be used in an AGC system to provide ripple-free gain control signals, while rapidly following any power transients in transmitted signals.
摘要:
Methods and systems are provided for an improved phase detector utilizing analog-to-digital converter (ADC) components. In an embodiment, the method includes from an ADC having a sampling clock signal that determines sampling instants, obtaining a first comparison value between an analog signal and a first threshold voltage at a first sampling instant, and obtaining a second comparison value between the analog signal and a second threshold voltage at a second sampling instant. The method further includes, from a supplemental circuit, obtaining a third comparison value between the analog signal and a third threshold voltage at a third sampling instant between the first and second sampling instants. The method further includes processing the first, second, and third comparison values to determine a phase relationship between the analog signal and the sampling clock.
摘要:
A peak detector circuit that responds rapidly to power transients, and yet is able to avoid interpreting data fluctuations as power transients by generating dual peak signals from an amplifier's differential output signal, where the dual peak signals have data ripple components that tend to cancel one another. The system and methods permit the peak detectors to be much more responsive to power transients by expanding their bandwidth (shortening the time constants) to the point that low frequency data components affect the individual peak detector signals, but the effects are cancelled out when the individual components are added together. The peak detector described herein may be used in an AGC system to provide ripple-free gain control signals, while rapidly following any power transients in transmitted signals.
摘要:
A method and structure for a content addressable memory (CAM) array having a plurality of memory cells. Each of the memory cells has capacitive storage devices, transistors connected to the storage devices, a wordline connected to and controlling the transistors, bitlines connected to the storage devices through the transistors, combined search and global bitlines connected to the capacitive storage devices. These cells are further arranged into columns, each containing multiplexers connected to the combined search and global bitlines, data-in lines connected to the multiplexers, and search-data lines connected to the multiplexers. Further, the multiplexers select between the data-in lines and the search-data lines to allow the combined search and global bitlines to be alternatively used as data lines and search lines. Also, in the invention each of the columns further has drivers between the multiplexers and the combined search and global bitlines. The drivers drive signals between the multiplexers and the combined search and global bitlines during search and write operations.
摘要:
A system and method is disclosed for simultaneously searching and refreshing a memory array of a dynamic content addressable memory (DCAM). According to the disclosed invention, the information stored in a row of DCAM cells being refreshed is transferred from the memory array into sense amplifiers, during a read phase of a refresh operation. A search for a matching entry can then be performed, with respect to the information that is transferred to the sense amplifiers. To determine if there is a match, search information is simultaneously compared to the information that has been transferred to the sense amplifiers and to the information that is stored in other rows of DCAM cells of said memory array. Finally, the refresh of that row is completed by restoring the information from the sense amplifiers to that row of DCAM cells.