Receiver Pre-Cancellation for Echo and Crosstalk Clipping Control

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Solution Overview

Problem

Existing receivers in wired networks face challenges in efficiently canceling echo and crosstalk, leading to clipping distortion of reception signals due to amplitude exceeding the acceptable range of analog-to-digital converters.

Innovation Solution

A receiver design incorporating a level decision module, digital-to-analog converter, analog-to-digital converter, and response module to determine levels and thresholds, convert signals, and generate a response signal for compensating echo and crosstalk, thereby reducing signal distortion and maintaining signal within the acceptable ADC range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If echo and crosstalk cancellation is performed using a conventional receiver with ADC, then the receiver can process reception signals, but the reception signal amplitude may exceed the acceptable range of the ADC causing clipping distortion

Engineering Contradiction:

Improvesignal processing reliabilityVSAvoidsignal amplitude precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The receiver performs preliminary echo and crosstalk cancellation before the ADC conversion by generating a pre-cancellation signal based on channel impulse responses and transmitting signals, then subtracting this from the received signal. This preliminary action ensures the signal amplitude remains within the ADC's acceptable range, preventing clipping distortion before it occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary pre-cancellation signal generation mechanism that acts between the signal source and the ADC. This intermediary process computes the expected echo and crosstalk components and subtracts them beforehand, serving as a mediator that protects the ADC from receiving signals with excessive amplitude that would cause clipping.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the receiver uses a higher-resolution ADC to avoid clipping distortion, then signal processing accuracy improves, but device complexity and cost increase

Engineering Contradiction:

Improvesignal conversion precisionVSAvoidreceiver structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the temporal parameter of signal processing by performing echo and crosstalk cancellation in the time domain before ADC conversion, rather than processing after conversion. This parameter change in processing timing allows the use of lower-resolution ADCs while maintaining signal integrity, as the harmful components are removed before conversion.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the need for high-resolution ADC hardware with a signal processing approach. Instead of relying on the ADC's inherent high resolution to handle large amplitude variations, the system uses computational methods to pre-process and reduce signal amplitude variations, substituting hardware requirements with algorithmic solutions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the receiver performs rough echo and crosstalk cancellation after ADC conversion, then the structure remains simple, but clipping distortion has already occurred causing failure in echo and crosstalk estimation

Engineering Contradiction:

Improvereceiver structure complexityVSAvoidsignal information accuracy

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The receiver performs preliminary echo and crosstalk cancellation before ADC conversion by generating a pre-cancellation signal based on channel impulse responses and transmitting signals, then subtracting this from the received signal. This preliminary action ensures the signal amplitude remains within the ADC's acceptable range, preventing clipping distortion before it occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8284878B2Receiver for echo and crosstalk cancellation and receiving method thereof

Publication Date: 2012.10.09 REALTEK SEMICON CORP

AI summary

A receiver for echo and crosstalk cancellation includes a level decision module, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC) and a response module. The level decision module determines plural levels and plural level magnitudes according to an estimated signal to generate a first digital signal. The DAC converts the first digital signal into a first analog signal according to the levels and the level magnitudes. The ADC receives a first difference signal between the receiving signal and the first analog signal, and converts the first difference signal into a second digital signal. According to the first digital signal, the response module generates a response signal compensating the second digital signal to generate a back-end input signal.