TELEVISION SIGNAL RECEIVER CAPABLE OF CANCELLING LINEAR AND NON-LINEAR DISTORTION

• US 20090115912A1
• Filed: 11/05/2007
• Published: 05/07/2009
• Est. Priority Date: 11/05/2007
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Liou, Ming-Luen, Chen, Yi-Fu
• Granted Patent: US 8,502,924 B2
• Time in Patent Office: Days
• US Class Current: 348/726
• 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; 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 a 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 a 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 a 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; 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 signal distortion in the IF 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 signal distortion comprises:

canceling a non-linear distortion at an IF band.

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

canceling an amplifier transfer curve distortion.

18. The method as claimed in claim 15, wherein the step of canceling the signal distortion comprises:

canceling a linear distortion at an IF band.

19. The method as claimed in claim 18, wherein the step of canceling the linear distortion comprises:

canceling an amplitude response distortion; and

canceling a group delay distortion;

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

20. 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 signal distortion in the IF conditioned signal to generate an IF distortion-cancelled signal; and

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

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

filtering the IF signal.

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

adjusting a signal power level of the IF signal.

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

digitizing the IF signal.

24. The method as claimed in claim 20, 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.