Receiver for echo and crosstalk cancellation and receiving method thereof

• US 8,284,878 B2
• Filed: 03/05/2009
• Issued: 10/09/2012
• Est. Priority Date: 03/05/2008
• Status: Active Grant

• Current Assignee: Realtek Semiconductor Corp.
• Original Assignee: Realtek Semiconductor Corp.
• Inventors: Shih, Chih-Yung, Huang, Liang-Wei, Kuo, Shieh-Hsing
• Primary Examiner(s): Timory, Kabir A
• Application Number:
  US12/398,186
• Publication Number:
  US 20090225912A1
• Time in Patent Office: 1,314 Days
• Field of Search: 375/346, 375/254, 375/348, 375/396
• US Class Current: 375/346
• CPC Class Codes: H04B 3/23 using a replica of transmitted signal in the time domain, e.g. echo cancellers
• CPC Class Codes: H04L 2025/03617 Time recursive algorithms H04L2025/03643 takes precedence

Abstract

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.

Claims

1. A receiver for echo and crosstalk cancellation comprising:

a level decision module for receiving an estimation signal and determining a plurality of levels and a plurality of level thresholds corresponding to the plurality of levels according to the estimation signal to generate a first digital signal;

a digital to analog converter for receiving the first digital signal and converting the first digital signal into a first analog signal according to the plurality of levels and the plurality of level thresholds;

an analog to digital converter for receiving a first difference signal corresponding to signal difference between a reception signal and the first analog signal and converting the first difference signal into a second digital signal;

a subtracting circuit, coupled to the digital to analog converter and the analog to digital converter, for generating the first difference signal corresponding to the signal difference between the reception signal and the first analog signal by subtracting the first analog signal, which is generated by the digital to analog converter, from the reception signal; and

a response module for receiving the first digital signal and generating a response signal according to the first digital signal;

wherein the response signal compensates the second digital signal to generate a back-end input signal.

2. The receiver of claim 1, wherein the reception signal is generated by a hybrid circuit.

3. The receiver of claim 1, wherein the response module is an adaptive filter adopting an adaptive algorithm.

4. The receiver of claim 3, wherein the adaptive algorithm is a least mean square (LMS) algorithm, a recursive least square (RLS) algorithm or a least square (LS) algorithm.

5. The receiver of claim 1, wherein the first difference signal is further processed by a first analog front-end circuit.

6. The receiver of claim 5, wherein the signal process of the first analog front-end circuit comprises at least a process of signal amplifying and signal filtering.

7. The receiver of claim 1 further comprising a back-end cancellation module for receiving the back-end input signal and generating the estimation signal according to a desired signal and the back-end input signal.

8. The receiver of claim 7, wherein the back-end cancellation module comprises:

an equalizer for receiving a second difference signal corresponding to signal difference between the estimation signal and the back-end input signal and equalizing the second difference signal to generate a first signal;

an error slicer for receiving a first signal and slicing the first signal to generate an error signal; and

an estimating unit for receiving the error signal and the desired signal and generating the estimation signal according to the error signal and the desired signal.

9. The receiver of claim 8, wherein the estimating unit is an adaptive filter adopting an adaptive algorithm.

10. The receiver of claim 9, wherein the adaptive algorithm is a least mean square (LMS) algorithm, a recursive least square (RLS) algorithm or a least square (LS) algorithm.

11. The receiver of claim 1, wherein the number of the plurality of levels is odd.

12. The receiver of claim 1, wherein the reception signal is further processed by a second front-end circuit.

13. The receiver of claim 12, wherein the signal process of the second analog front-end circuit comprises at least one of signal amplifying and signal filtering.

14. A receiving method for echo and crosstalk cancellation comprising:

determining a plurality of levels and a plurality of level thresholds corresponding to the plurality of levels according to an estimation signal;

generating a first digital signal according to the plurality of levels and the estimation signal;

using a digital to analog converter to convert the first digital signal into a first analog signal according to the plurality of levels and the plurality of level thresholds;

converting a first difference signal corresponding to signal difference between a reception signal and the first analog signal into a second digital signal;

generating the first difference signal corresponding to the signal difference between the reception signal and the first analog signal by subtracting the first analog signal, which is generated by the digital to analog converter, from the reception signal; and

generating a response signal for compensating the second digital signal according to the first digital signal so as to generate a back-end input signal.

15. The receiving method of claim 14, wherein the reception signal is generated by a hybrid circuit.

16. The receiving method of claim 14, wherein generating the response signal for compensating the second digital signal according to the first digital signal comprises:

providing an adaptive filter adopting an adaptive algorithm; and

receiving the first digital signal through the adaptive filter to generate the response signal.

17. The receiving method of claim 16, wherein the adaptive algorithm is a least mean square (LMS) algorithm, a recursive least square (RLS) algorithm or a least square (LS) algorithm.

18. The receiving method of claim 14 further comprising:

generating an error signal according to a second difference signal corresponding to difference between the back-end input signal and the estimation signal; and

generating the estimation signal according to the error signal and a desired signal.

19. The receiving method of claim 18, wherein generating the estimation signal comprises:

providing an adaptive filter adopting an adaptive algorithm; and

receiving the error signal and the desired signal through the adaptive filter to generate the estimation signal.

20. The receiving method of claim 19, wherein the adaptive algorithm is a minimum mean square error (MMSE) algorithm, a recursive least square (RLS) algorithm or a least square (LS) algorithm.

21. The receiving method of claim 14 further comprising:

performing at least one of an amplifying process and a filtering process on the reception signal.

22. The receiving method of claim 14 further comprising:

performing at least one of an amplifying process and a filtering process on the first difference signal.

23. The receiving method of claim 14, wherein the number of the plurality of levels is odd.