Echo cancellation and baseband drift cancellation circuit applied to Ethernet

Abstract

The invention provides an echo cancellation and baseband drift cancellation circuit applied to the Ethernet. The echo cancellation and baseband drift cancellation circuit comprises two DACs, a differential filter module, an amplifier module and a current steering DAC module, wherein the first DAC is used for providing digital-to-analog conversion and transmission of a target digital signal, and the second DAC is used for copying the target digital signal and performing digital-to-analog conversion; the output end of the first DAC and the output end of the second DAC are connected with two differential input ends of the differential filter module. The amplifier module is used for providing reference voltage for the output of the echo cancellation circuit; the output end of the amplifier module is connected with the third input end of the differential filter module; the current-steering DAC module is used for providing baseband drift compensation current; the output end of the current steering DAC module is connected with the output end of the differential filter module. The band-pass filter can isolate direct current input signals and filter out-of-band high-frequency interference signals. The baseband drift elimination circuit has the advantages of simple structure, low power consumption and small area; and the problems of voltage jitter and imbalance do not exist.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to an echo cancellation and baseband drift cancellation circuit applied to the Ethernet. Background technique [0002] The analog receiver front-end circuit is the key module of the 100 / 1000 Base-TX Ethernet physical layer interface chip, and its system block diagram is as follows figure 1 shown. The analog receiving front-end circuit mainly realizes the following functions: [0003] (1) In order to reduce the number of external cables, it is required to transmit and receive on the same pair of cables, which causes the analog input signal of the receiving circuit to be the superposition of the sending signal and the receiving signal, which requires the use of echo cancellation (EchoCanceler) circuit After the signal sent by the machine is eliminated, the signal received by the machine is processed. [0004] (2) Due to the high-pass characteristics of the transformer in the ...

AI Technical Summary

Problems solved by technology

[0015] The invention provides an echo cancellation and baseband drift cancellation circuit applied to Ethernet, which is used to solve the problem that the echo signal in the echo cancellation circuit in the prior art cannot be completely eliminated, the high-frequency signal cannot be filtered out, and the circuit in the baseband drift circuit The defects of large power consumption and area and unstable circuit realize the elimination of echo signals and the filtering of high-frequency signals and the reduction of power consumption in the baseband drift circuit and the stability of the circuit

Images