Abstract:
An equalizer that compensates for non-linear effects resulting from a transmitter, a receiver, and/or a communication channel in a communication system. A non-linear decision feedback equalizer compensates for the non-linear effects impressed onto a received symbol by selecting between equalization coefficients based upon a previous received symbol. The received symbol may be represented in form of logic signals based on the binary number system. When the previous received symbol is a binary zero, the non-linear decision feedback equalizer selects an equalization coefficient corresponding to binary zero to compensate for the non-linear effects impressed onto the received symbol. When the previous received symbol is a binary one, the non-linear decision feedback equalizer selects an equalization coefficient corresponding to binary one to compensate for the non-linear effects impressed onto the received symbol.
Abstract:
An equalizer is disclosed that compensates for non-linear effects resulting from a transmitter, a receiver, and/or a communication channel in a communication system. A non-linear decision feedback equalizer compensates for the non-linear effects impressed onto a received symbol by selecting between equalization coefficients based upon a previous received symbol. The received symbol may be represented in form of logic signals based on the binary number system. The two symbols most commonly chosen to represent the two logic values taken on by binary symbols are binary zero and binary one. When the previous received symbol is a binary zero, the non-linear decision feedback equalizer selects an equalization coefficient corresponding to binary zero to compensate for the non-linear effects impressed onto the received symbol. Likewise, when the previous received symbol is a binary one, the non-linear decision feedback equalizer selects an equalization coefficient corresponding to binary one to compensate for the non-linear effects impressed onto the received symbol.
Abstract:
According to one general aspect, an apparatus may include a clock channel, a shielding tunnel, and clock repeaters. In various embodiments, the clock channel may be configured to carry the clock signal, and may include a portion of a metal layer of an integrated circuit. In some embodiments, the shielding tunnel may be configured to shield, in at least four directions, the clock channel from other signals, and may include portions of a at least three metal layers of the integrated circuit. The shielding tunnel may be connected to the positive and negative supplies in order to provide the required power for the clock repeaters.
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:
Embodiments of threshold adjustment circuits are disclosed. An example circuit includes a first differential pair of first and second thin oxide transistors. The first and second thin oxide transistors decrease a DC voltage component of a first or second component of an input signal of the circuit. The example circuit further includes a second differential pair of third and fourth thin oxide transistors. The second and third thin oxide transistors increase a DC voltage component of the first or the second component of the input signal. The example circuit also includes a power supply for providing a supply voltage to the circuit, the power supply having a voltage level above a reliability level of the thin oxide transistors. In the example circuit, each of the differential pair thin oxide transistors is switched by a signal that keeps each of the first, second, third, and fourth thin oxide transistors operating in saturation.
Abstract:
A communication receiver includes a decision feedback equalizer and clock and data recovery circuit. Various adaptation loops may control the operation of the decision feedback equalizer, the clock and data recovery circuit, a continuous time filter, a threshold adjust circuit, and an analog-to-digital clock that is used to generate soft decision data for some of the adaptation loops.
Abstract:
A continuous time filter having a first stage and a second stage. A first stage adjusts a bandwidth of the signal. A second stage adjusts bandwidth of the signal subsequent to the first stage. Each stage includes a first capacitor with a first capacitance and a second capacitor with a second capacitance for providing uniform step sizes for bandwidth adjustment. The continuous time filter may include a plurality of cascaded stages including the first stage and the second stage. In addition, a bandwidth adjustment across the first stage and the second stage may be controlled using a semi-interleaved thermometer coding to achieve a cascaded effect for the bandwidth adjustment.
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:
A phase lock loop with multiple divider paths is presented herein. The phase lock loop can be used to provide a wide range of frequencies. The phase lock loop can also be used as a portion of a clock multiplier unit or a clock data and recovery unit.
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.