Method and apparatus for reception of terrestrial digital television signals

• US 20020163593A1
• Filed: 08/06/2001
• Published: 11/07/2002
• Est. Priority Date: 03/30/2001
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Liu, Tianmin, Perlow, Randall B.
• Granted Patent: US 7,034,893 B2
• Time in Patent Office: Days
• US Class Current: 348/614
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/03057 with a recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 27/06 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 5/211 Ghost signal cancellation H04N23/81 takes precedence

Abstract

A digital television signal is intercepted by a plurality of antennas to produce a corresponding plurality of input signals. The antennas have different directionality so they can be combined in a way that reduces multipath echoes. In one embodiment, the antennas are arranged to operate in a diversity or scanned array mode. In another embodiment, the antennas are arranged to operate in a adaptive phased array mode. The input signals intercepted by the antenna are subjected to vestigial sideband (VSB) processing to produce a single VSB processed signal, which is decoded to form a display drive signal. A plurality of input signals in a VSB receiver having a plurality of antennas with different directionality are evaluated to determine how the input signals should be combined to reduce multipath echoes. The quality of the input signals from the antennas is evaluated at one of a number of different points in the VSB receiver, such as at the outputs of the antennas, the outputs of the VSB processors, or the output of the forward error correction (FEC) decoder. Within the VSB processors themselves, the quality of the input signals can be evaluated at a number of different points, including the outputs at the front end, the outputs at the back end, or inside the back end the outputs at the feed forward equalizer.

Claims

1. A method for receiving a digital television signal comprising the steps of:

intercepting a digital television signal with a plurality of antennas having different directionality to produce a corresponding plurality of input signals;

combining the input signals to reduce multi-path echoes;

subjecting the input signals to VSB processing to produce a single VSB processed signal;

decoding the VSB processed signal to form a display drive signal.

2. The method of claim 1, in which the combining step weights the input signals to produce a combined signal.

3. The method of claim 2, in which the weights of all the input signals but one are zero.

4. The method of claim 2, in which the weights of all the input signals are non-zero.

5. The method of claim 2, in which the weights of all the input signals are different.

6. The method of claim 1, in which the intercepting step uses a plurality of fixed beam antennas having different directionality.

7. The method of claim 1, in which the intercepting step uses a plurality of swept beam antennas having the same directionality.

8. The method of claim 1, in which the step of combining the input signals takes place before the step of subjecting the input signals to VSB processing.

9. The method of claim 1, in which the step of combining the input signals takes place after the step of subjecting the input signals to VSB processing.

10. The method of claim 1, additionally comprising the step of forward error correcting the VSB signal before decoding the VSB signal.

11. The method of claim 1, in which the intercepting step intercepts a terrestrial signal.

13. The receiver of claim 12, in which the connecting means comprises a switch.

14. The receiver of claim 13, in which the radio signal comprises a digital television signal and the signal processor comprises a VSB processor.

15. The receiver of claim 14, in which the radio signal comprises a digital television signal with QAM modulation and the signal processor comprises a VSB processor with forward error correction.

17. The receiver of claim 16, in which the connecting means comprises a switch.

18. The receiver of claim 17, in which the utilization circuit comprises a VSB receiver and forward error correction means.

19. The receiver of claim 18, in which the radio signal comprises a digital television signal with QAM modulation and the utilization circuit comprises a VSB processor with forward error correction.

26. The method of claim 1, in which the combining step evaluates the quality of the input signals and the subjecting step produces the single VSB signal based on the evaluation.

12. A receiver for intercepting a modulated radio signal, the receiver comprising:

a plurality of antennas having different directionality to produce a corresponding plurality of input signals;

means for evaluating the quality of the plurality of input signals;

a signal processor for demodulating a signal applied to its input; and

means responsive to the evaluating means for connecting one of the antennas to the input of the signal processor based on the quality of the input signals

16. A receiver for intercepting a modulated radio signal, the receiver comprising:

a plurality of antennas having different directionality to produce a corresponding plurality of input signals;

means for evaluating the quality of the plurality of input signals;

a plurality of signal processors connected to the respective antennas for demodulating the respective plurality of input signals;

a utilization circuit; and

means responsive to the evaluating means for connecting one of the signal processors to the utilization circuit based on the quality of the input signals.

20. The receiver of 19 , in which the utilization circuit additionally comprises an MPEG decoder.

21. The receiver of claim of 20, in which the signal processors each have a tuner and the receiver has means for setting the tuners to the same channel in a diversity or scanned array mode.

22. The receiver of claim 21 in which the receiver also has means for setting the tuners to different channels in a two signal mode and means responsive to the evaluating means in the two signal mode for connecting both of the signal processors to one or the other or both of the antennas in the two channel mode.

24. The receiver of claim 23, in which the one or more criteria comprise one or more of the SNR, SER, SMS, FEC, FFE, and DFE.

25. The receiver of claim 23, in which the one or more criteria comprise SNR and one or more of the, SER, SMS, FEC, FFE, and DFE.

27. The method of claim 26, in which the digital television signal is arranged as video lines and the video lines are arranged as video frames such that combining step evaluates the quality of the input signals on a line by line or frame by frame basis.

29. The method of claim 28, in which the television signal is a digital television signal.

23. A receiver for intercepting a modulated radio signal, the receiver comprising:

a plurality of antennas having different directionality to produce a corresponding plurality of input signals;

means for evaluating the quality of one or more criteria of the input signals;

a plurality of signal processors connected to the respective antennas for demodulating the respective plurality of input signals;

a utilization circuit; and

means responsive to the evaluating means for connecting one of the signal processors to the utilization circuit based on the quality of the input signals.

28. A method for receiving a television signal arranged as video lines and the video lines are arranged as video frames, the method comprising the steps of:

intercepting a digital television signal with a plurality of antennas having different directionality to produce a corresponding plurality of input signals;

evaluating the quality of the input signals on a line by line or frame by frame basis;

combining the evaluated input signals to produce a single VSB processed signal that reduces the effects of multi-path echoes;

decoding the VSB processed signal to form a display drive signal.

30. A receiver for intercepting a modulated radio signal having a defined format, the receiver comprising:

a plurality of antennas having different directionality to produce a corresponding plurality of input signals;

means for evaluating the quality of the plurality of input signals on a line by line or frame by frame basis;

a signal processor for demodulating a signal applied to its input; and

means responsive to the evaluating means for connecting one of the antennas to the input of the signal processor based on the quality of the input signals.