Communications receiver equalizer

A technology of equalizer and inductor, which is applied in the shaping network of transmitter/receiver, digital transmission system, baseband system components, etc. It can solve the problems of clock and data recovery circuit failure, poor signal quality, etc.

Active Publication Date: 2017-08-18
NXP USA INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the ISI is severe, then the received signal quality is po...

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  • Communications receiver equalizer
  • Communications receiver equalizer
  • Communications receiver equalizer

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Embodiment Construction

[0017] Due to the foregoing, transmit and / or receive equalization may be provided to compensate for losses associated with analog signals to be transmitted over a communication channel. In communication systems, equalization is the process of correcting channel-induced distortions caused by inherent losses within the communication channel (ie, the aforementioned inherent ISI characteristics of the communication channel). Equalizers are filters that can be adjusted to compensate for channel distortion. Since the communication channel essentially acts as a low pass filter, the function of the equalizer is to equalize the levels between the various frequencies of the transmitted signal. In some aspects, such equalizers act as high-pass filters. The basic problem is that the eye diagram of the received signal (i.e., the oscilloscope display of the received signal that can provide an indication of the effects of channel noise and / or ISI) is somewhat closed, which can introduce ina...

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Abstract

A continuous-time linear equalizer implementing enhanced analog delay cells with gain-peaking characteristics and a constant delay time is provided. A receiver feed-forward equalizer architecture implements a gain-stage chain, analog multipliers for correcting coefficients, and a linear combiner as an analog summation circuit. Each of the gain stages produces linear gain peaking and presents a constant delay-time (through calibrations) at each stage. Each delay cell includes a transconductance stage configured to convert a differential input voltage signal to a differential output current signal, wherein the transconductance stage includes a differential pair of first and second transistors coupled in a source degeneration configuration, a negative resistance network coupled in parallel with a tunable resistor network, and shunt inductive circuitry coupled in parallel with the negative resistance network. The delay cells also include a transimpedance stage configured to convert the differential output current signal received from the transconductance stage to a differential output voltage signal, wherein the transimpedance stage implements a first transimpedance amplifier coupled in series with a first shunt inductive circuit. The shunt inductive circuits may include inductorless inductor circuit elements.

Description

technical field [0001] The present invention relates generally to the field of communication devices, and more particularly to a receiver feedforward equalizer having a continuous time delay unit with linear equalization capability. Background technique [0002] Inter-symbol interference ("lSI") is an unavoidable consequence of wired and wireless communication systems. The one and zero bits of the data stream are converted to analog signals (thus becoming "symbols") for transmission over a transmission link (also referred to herein as a "communication channel"). Due to various properties of the medium (of the communication channel) used and the distance the signal travels (through the communication channel), the symbols of a received signal tend to become elongated and smear each other. This spreading and smearing of symbols such that energy from one symbol affects the next in such a way that the received signal has a higher probability of being interpreted incorrectly is c...

Claims

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Application Information

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IPC IPC(8): H04L25/03
CPCH04L25/03019H04L25/03885H04L25/0272H04L25/0292H03K5/134H03K2005/00019
Inventor 常奕城
Owner NXP USA INC
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