# US 7,280,493 B2 · Method for hardware reduction in echo canceller and near-end crosstalk canceller

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- Number: US 7,280,493 B2
- Document ID: US7280493B2
- Status: Granted
- Kind: B2
- Application number: 10/064,238
- Filed: 2002-06-25
- Published: 2003-11-20
- Granted: 2007-10-09
- Earliest claimed: 2002-05-15
- Assignees: Topic Semiconductor Corp.
- Inventors: Claymens Lee
- Web page: https://patentgrep.com/patent/US7280493B2

## CPC

- H04B 3/23: using a replica of transmitted signal in the time domain, e.g. echo cancellers
- H04B: TRANSMISSION

## Abstract

The present invention provides a method for hardware reduction in the echo canceller and the near-end crosstalk canceller. The method applies an N (N is a positive integer) times divide frequency sampling operation onto the input data list of the echo canceller first (and the near-end crosstalk canceller). Then, it applies an N times multiply frequency sampling operation onto the output data list of the echo canceller (and the near-end crosstalk canceller) to generate a multiplied frequency data list. Afterwards, a low pass filter operation is applied to the multiplied frequency data list to generate a low pass data list to eliminate the echo signal (and the near-end crosstalk signal). The present invention reduces the number of the taps in the echo canceller and the near-end crosstalk canceller by using the digital signal process technique. Therefore, the area of the whole communication IC occupied by the echo canceller and the near-end crosstalk canceller can be reduced.

## Claims

### Claim 1

A method for hardware reduction in an echo canceller, comprising:
applying an N (N is a positive integer) times divide frequency sampling operation onto an input data list of the echo canceller, and the frequency-divided input data list is then transmitted to the echo canceller for performing an echo signal cancellation operation on the frequency-divided input data list;
applying an N times multiply frequency sampling operation onto an output data list of the echo canceller to generate a multiplied frequency data list; and
applying a low pass filter operation with a low pass filter onto the multiplied frequency data list to generate a low pass data list, wherein a cutoff frequency of the low pass filter is 1/(2N) times of the sampling frequency of the input data list.

### Claim 2 (depends on 1)

The method of claim 1, wherein a sampling frequency of the N times divide frequency sampling operation is adjustable.

### Claim 3 (depends on 1)

The method of claim 1, wherein a sampling frequency of the N times multiply frequency sampling operation is adjustable.

### Claim 4 (depends on 1)

The method of claim 1, wherein the low pass data list is used to eliminate a far-end echo signal.

### Claim 5 (depends on 1)

The method of claim 1, wherein the method is used in a receiver inside a transceiver.

### Claim 6 (depends on 1)

The method of claim 1, wherein the echo canceller adopts a finite impulse response filter.

### Claim 7

A method for hardware reduction in a near-end crosstalk canceller, comprising:
applying an N (N is a positive integer) times divide frequency sampling operation onto an input data list of the near-end crosstalk canceller;
applying an N times multiply frequency sampling operation onto an output data list of the near-end crosstalk canceller to generate a multiplied frequency data list; and
applying a low pass filter operation with a low pass filter onto the multiplied frequency data list to generate a low pass data list, wherein a cutoff frequency of the low pass filter is 1/(2N) times of the sampling frequency of the input data list.

### Claim 8 (depends on 7)

The method of claim 7, wherein a sampling frequency of the N times divide frequency sampling operation is adjustable.

### Claim 9 (depends on 7)

The method of claim 7, wherein a sampling frequency of the N times multiply frequency sampling operation is adjustable.

### Claim 10 (depends on 7)

The method of claim 7, wherein the low pass data list is used to eliminate a near-end crosstalk signal.

### Claim 11 (depends on 7)

The method of claim 7, wherein the method is used in a receiver inside a transceiver.

### Claim 12 (depends on 7)

The method of claim 7, wherein the near-end crosstalk canceller adopts a finite impulse response filter.