Time-domain adaptive equalizer with overlay structure

Abstract

The related time-domain adaptive equalizer with overlay structure overlays the backward part of forward feedback filter to the some taps of feedback filter on time domain to eliminate the strong multi-path signal. This invention improves equalizer performance to anti strong multi-path signal as well as its convergence speed.

Description

technical field [0001] The invention relates to a time-domain adaptive equalizer, in particular to a time-domain adaptive equalizer with an overlapping structure, which improves the ability of the time-domain equalizer to resist strong multipath signals through the overlapping structure. It belongs to the improvement made to the adaptive equalizer. Background technique [0002] Equalizers are a very important component in the practical application of many different digital information such as voice, data and video communications. Equalizers are used as echo cancellers (compensators) for loudspeakers in full-duplex communications, video deghosting in digital television or digital cable transmission, signal conditioners for wireless modems and wireless phones, etc. [0003] In the process of signal transmission, due to the existence of multipath signals in the channel, it will bring inter-symbol interference (ISI), and inter-symbol interference is an important cause of errors...

AI Technical Summary

Problems solved by technology

When the amplitude of the secondary path is smaller than the main path, the amplitude of these derived multipaths will decrease step by step, and the corresponding coefficients will also decrease step by step. The number of stages is limited, but as long as the feedforward filter is long enough, it can still be stable on the limited tap coefficients, but when When the secondary path signal is stronger or equal to the main path signal, the derivative multipath amplitude is always greater than or equal to the main path. As long as it is a feedforward filter with a limited number of stages, it will definitely cause strong derivative multipath to fall outside the feedforward filter However, these effects can never be counteracted, resulting in the main path signal being completely submerged in multipath and noise, the eye diagram is completely closed, and the coefficients cannot converge

[0008]On the other hand, when the strong secondary path falls in the feedback filter part of the decision feedback equalizer, although a corresponding coefficient can be grown in the feedback filter part, namely Yes (there is no multipath propagation), but due to the phenomenon of error diffusion in the feedback filter, and the probability of misjudgment increases due to the complete closure of the eye diagram, the error diffusion is serious, which will cause the coefficients of the feedback filter part of the decision feedback equalizer to converge unstable

In short, the traditional time-domain linear adaptive equalization cannot generate appropriate tap coefficients to stably resist harsh multipath effects

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