Abstract:
A method for communicating data includes equalizing received data to reduce channel related distortion in the received data. A clock having frequency and/or phase fixed relative to the equalized data is extracted from the equalized data. The extracted clock is used to clock a retimer to generate recovered data.
Abstract:
A variable gain amplifier including a stage. The stage having a set of switchable differential pairs. The stage providing a gain range to a signal and adjusting a gain of the signal. At least one differential pair in each stage is permanently enabled. The variable gain amplifier may include a plurality of cascaded stages including the stage. In addition, the variable gain amplifier may be adjusted through an interleaved thermometer coding method.
Abstract:
Methods, systems, and apparatuses for calibration of analog to digital converters (ADC) are described herein. In an aspect, an ADC includes a plurality of slices. Each slice includes a digital to analog converter (DAC), a comparator, and a digital processing unit (DPU). The digital processing unit is electrically connected to the comparator and the DAC. In another aspect, an analog-to-digital converter includes an input module and an analog to digital converter core configured to receive an analog input from the input module and generate a digital output. The ADC is configured to adjust a precision of the analog to digital converter core based on a quality of the analog input signal.
Abstract:
A method and apparatus for an automatic gain control circuit (AGC) that utilizes freezing and unfreezing states. A freezing process moves the AGC into a TRANSITION state from a NORMAL state, based on net change of VGA gain control codes over a monitoring time window. The freezing process then moves the AGC into a FROZEN state from the TRANSITION state, based on net change of VGA gain control codes over the monitoring time window. An unfreezing process moves the AGC into the NORMAL state from the FROZEN state, based on signal amplitude changes at the output of the VGA or other parameters of the VGA.
Abstract:
A variable gain amplifier including a stage. The stage having a set of switchable differential pairs. The stage providing a gain range to a signal and adjusting a gain of the signal. At least one differential pair in each stage is permanently enabled. The variable gain amplifier may include a plurality of cascaded stages including the stage. In addition, the variable gain amplifier may be adjusted through an interleaved thermometer coding method.
Abstract:
A threshold adjustment circuit including: a current DAC for supplying or sinking a varying current; a differential pair of thin oxide transistors coupled to the DAC and coupled together at a common source node; a power supply for providing a supply voltage having a voltage level above reliability of the thin oxide transistors; and a third transistor for maintaining voltage of the common source node above a predetermined level and to disable the threshold adjustment circuit. The bulk and source of each of the differential pair thin oxide transistors is coupled to the common source node and each of the differential pair thin oxide transistors is switched by a signal to keep each of the differential pair thin oxide transistors in saturation region.
Abstract:
Data error such as mean square error may be reduced in a system such as a communication receiver using a dithering algorithm that adjusts one or more parameters in the system. The dithering algorithm may be applied to more than one parameter. The dithering algorithm may include a state machine to alter the rate of change dependent on the state of the dithering algorithm.
Abstract:
In an integrated decision feedback equalizer and clock and data recovery circuit one or more flip-flops and/or latches may be shared. One or more flip-flops and/or latches may be used in retiming operations in a decision feedback equalizer and in phase detection operations in a clock recovery circuit. Outputs of the flip-flops and/or latches may be used to generate feedback signals for the decision feedback equalizer. The output of a flip-flop and/or latches may be used to generate signals that drive a charge pump in the clock recovery circuit.
Abstract:
Method and circuitry for improving the accuracy and efficiency of a phase-locked loop. More specifically, the present invention relates to a method and device for monitoring the frequency discrepancy between two signals in conjunction with at least one data signal so as to improve the accuracy and efficiency of a phase-locked loop. In one embodiment of the present invention, two counters are used to check the frequency differential between a VCO signal and an external reference or input signal. An adjustable threshold is provided to determine whether the frequencies of the two signals are considered to be in a frequency-locked mode. A pair of flip-flops is used to minimize any erroneous detection of frequency discrepancy by validating two consecutive results of the frequency differential check. In addition, a data present signal is used to control the transition between the phase-locked mode and the frequency-locked mode to minimize the potential data loss.
Abstract:
Various methods and circuits for implementing high speed peak amplitude comparison. The invention achieves higher speed of operation by eliminating the slow feedback loop commonly employed in peak detection. In one embodiment, the invention directly compares a signal that represents the peak amplitude of the input signal minus a small voltage drop, to a modified reference voltage. The modified reference voltage corresponds to the reference voltage that is adjusted to compensate for the small voltage drop in the maximum input voltage. In another embodiment, the invention implements a differential version of the peak amplitude comparator to obtain better noise rejection and reduced effective offset among other advantages.