Television signal receiver capable of cancelling linear and non-linear distortion

• US 8,502,924 B2
• Filed: 11/05/2007
• Issued: 08/06/2013
• Est. Priority Date: 11/05/2007
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Liou, Ming-Luen, Chen, Yi-Fu
• Primary Examiner(s): VU, NGOC K
• Application Number:
  US11/934,892
• Publication Number:
  US 20090115912A1
• Time in Patent Office: 2,101 Days
• Field of Search: 348725-726
• US Class Current: 348/725
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 5/21 Circuitry for suppressing or minimising disturbance, e.g. moiré or halo
• CPC Class Codes: H04N 5/455 Demodulation-circuits
• CPC Class Codes: H04N 5/62 Intercarrier circuits, i.e. heterodyning sound and vision carriers H04N5/607 takes precedence

Abstract

A television signal receiver comprises: a tuner, an optional IF conditioner, an IF distortion canceller, and an IF demodulator. The tuner selects one channel from a radio frequency television signal to generate an intermediate frequency signal. The IF conditioner outputs an IF conditioned signal. The IF distortion canceller cancels a signal distortion in the IF signal or the IF conditioned signal to generate an IF distortion-cancelled signal. The IF demodulator demodulates the IF distortion-cancelled signal to output a baseband signal.

Claims

1. A television signal receiver, comprising:

a tuner for selecting one channel from a radio frequency (RF) television signal to generate an intermediate frequency (IF) signal;

an IF distortion canceller coupled to the tuner for canceling a signal distortion in the IF signal to generate an IF distortion-cancelled signal, wherein the IF distortion canceller comprises a front-end portion having an input to receive the IF signal and cancel non-linear distortion in the IF signal, wherein the IF distortion canceller further comprising a back-end portion having an input to receive an output of the front-end portion and cancel linear distortion carried in the IF signal, the back-end portion outputting the IF distortion-cancelled signal; and

an IF demodulator coupled to the IF distortion canceller for demodulating the IF distortion-cancelled signal to output a baseband signal.

2. The television signal receiver as claimed in claim 1, wherein the IF distortion canceller comprises:

non-linear distortion canceling circuitry operated at an IF band for canceling the non-linear distortion in the IF signal.

3. The television signal receiver as claimed in claim 2, wherein the non-linear distortion canceling circuitry comprises:

a level-mapping device having a programmable transfer curve for canceling a tuner transfer curve distortion.

4. The television signal receiver as claimed in claim 1, wherein the IF distortion canceller comprises:

linear distortion canceling circuitry operated at an IF band for canceling the linear distortion in the IF signal.

5. The television signal receiver as claimed in claim 4, wherein the linear distortion canceling circuitry comprises:

an amplitude distortion canceller having a programmable amplitude response for canceling an amplitude response distortion;

wherein the amplitude response distortion comprises a tuner amplitude response from the tuner.

6. The television signal receiver as claimed in claim 4, wherein the linear distortion canceling circuit comprises:

a programmable filter having a programmable group delay for canceling a group delay distortion;

wherein the group delay distortion comprises a group delay precorrection performed by a transmitter, and a tuner group delay from the tuner.

7. The television signal receiver as claimed in claim 4, wherein the linear distortion canceling circuitry comprises:

a programmable digital filter having a programmable amplitude response and a programmable group delay for canceling an amplitude response distortion and a group delay distortion;

wherein the amplitude response distortion comprises an amplitude response distortion from the tuner;

wherein the group delay distortion comprises a group delay precorrection performed by a transmitter, and a tuner group delay form the tuner.

8. The television signal receiver as claimed in claim 1 further comprising:

a controller coupled to the IF distortion canceller for generating a control signal to program the IF distortion canceller to cancel distortion in the IF signal.

9. A television signal receiver, comprising:

a tuner for selecting one channel from a radio frequency (RF) television signal to generate an intermediate frequency (IF) signal;

an IF conditioner coupled to the tuner for conditioning the IF signal to generate an IF conditioned signal;

an IF distortion canceller coupled to the IF conditioner for canceling a signal distortion in the IF conditioned signal to generate an IF distortion-cancelled signal, wherein the IF distortion canceller comprises a front-end portion having an input to receive the IF conditioned signal and cancel non-linear distortion in the IF signal, wherein the IF distortion canceller further comprising a back-end portion having an input to receive an output of the front-end portion and cancel linear distortion carried in the IF signal, the back-end portion outputting the IF distortion-cancelled signal; and

an IF demodulator coupled to the IF distortion canceller for demodulating the IF distortion-cancelled signal to output a baseband signal.

10. The television signal receiver as claimed in claim 9, wherein the IF conditioner comprises:

an IF filter for filtering the IF signal.

11. The television signal receiver as claimed in claim 9, wherein the IF conditioner comprises:

an amplifier for adjusting a signal power level of the IF signal.

12. The television signal receiver as claimed in claim 9, wherein the IF conditioner comprises:

a quantizer for digitizing the IF signal.

13. The television signal receiver as claimed in claim 9, wherein the IF conditioner comprises:

a frequency shifter for moving a signal spectrum of the IF signal to an IF band in a predetermined depth.

14. The television signal receiver as claimed in claim 9, wherein the IF distortion canceller cancels a signal distortion generated by the IF conditioner.

15. A method of receiving a radio frequency (RF) signal, comprising:

selecting one channel from the RF signal to generate an intermediate frequency (IF) signal;

canceling a non-linear signal distortion in the IF signal to generate an intermediate conditioned signal;

canceling a linear signal distortion in the intermediate conditioned signal to generate an IF distortion-cancelled signal; and

demodulating the IF distortion-cancelled signal to output a baseband signal.

16. The method as claimed in claim 15, wherein the step of canceling the non-linear signal distortion comprises:

canceling an amplifier transfer curve distortion.

17. The method as claimed in claim 15, wherein

canceling the linear signal distortion comprises canceling an amplitude response distortion;

and

canceling a group delay distortion;

wherein the group delay distortion comprises a group delay precorrection and a selecting group delay introduced during the step of selecting one channel from the RF television signal.

18. A method of receiving a radio frequency (RF) signal, comprising:

selecting one channel from the RF signal to generate an intermediate frequency (IF) signal;

conditioning the IF signal to generate an IF conditioned signal;

canceling a non-linear signal distortion in the IF conditioned signal to generate an intermediate conditioned signal;

canceling a linear signal distortion in the intermediate conditioned signal to generate an IF distortion-cancelled signal; and

demodulating the IF distortion-cancelled signal to output a baseband signal.

19. The method as claimed in claim 18, wherein the step of conditioning the IF signal comprises:

filtering the IF signal.

20. The method as claimed in claim 18, wherein the step of conditioning the IF signal comprises:

adjusting a signal power level of the IF signal.

21. The method as claimed in claim 18, wherein the step of conditioning the IF signal comprises:

digitizing the IF signal.

22. The method as claimed in claim 18, wherein the step of conditioning the IF signal comprises:

moving a signal spectrum of the IF signal to an IF band in a predetermined depth.