Method and apparatus for combating co-channel NTSC interference for digital TV transmission

• US 5,452,015 A
• Filed: 02/10/1994
• Issued: 09/19/1995
• Est. Priority Date: 02/10/1994
• Status: Expired due to Term

• Current Assignee: Funai Electric Co., Ltd.
• Original Assignee: Philips Electronics North America Corporation (Koninklijke Philips N.V.)
• Inventors: Hulyalkar, Samir N.
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Murrell, Jeffrey S.
• Application Number:
  US08/197,773
• Time in Patent Office: 586 Days
• Field of Search: 348/607, 348/726, 348/608, 348/21, 348/611, 348/409, 348/618, 455/296, 455/308, 455/63, 375/99, 375/102, 375/103
• US Class Current: 348/608
• CPC Class Codes: H04L 2025/03382 Single of vestigal sideband
• CPC Class Codes: H04L 2025/03496 as a prediction filter
• CPC Class Codes: H04L 25/03318 Provision of soft decisions
• 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 rejection filter for use at an ATV receiver which is designed to process co-channel interference so as to produce at the filter output of the filter, a residual interference spectrum which is as flat as possible. The filter exploits the fact that only the picture and the sound carriers need to be sufficiently attenuated and cancels NTSC co-channel interference with only a small degradation in performance when AWGN is also present.

Claims

1. A television receiver comprising:

means for receiving a transmitted signal having an encoded digital television signal component and a co-channel interference component;

means for flattening the frequency spectrum of the co-channel interference component to produce a filtered encoded digital television signal from the transmitted signal, said means for flattening including a prediction filter having fixed coefficients; and

decoder means for decoding the filtered encoded digital television signal.

2. A television receiver as claimed in claim 1, wherein the encoded digital television signal is a precoded encoded digital television signal, and said prediction filter operates on the transmitted signal.

3. A television receiver as claimed in claim 1, wherein said prediction filter further has a gain factor, and said coefficients are restricted to values in the set {-1,0,+1}.

4. A television receiver as claimed in claim 1, wherein said prediction filter operates on a difference signal, said difference signal being the difference between the transmitted signal and a past-decision signal.

5. A television receiver as claimed in claim 1, wherein said prediction filter operates on a difference signal, said difference signal being the difference between the transmitted signal delayed by a time interval and a past-decision signal delayed by said time interval.

6. A television receiver as claimed in claim 5, wherein the time interval is substantially equal to a NTSC line interval delay.

7. A television receiver comprising:

means for receiving a transmitted signal having an encoded digital television signal component which has had its symbols interleaved at a transmitter and a co-channel interference component;

means for flattening the frequency spectrum of the co-channel interference component to produce a filtered encoded digital television signal from the transmitted signal, said means for flattening including a prediction filter having fixed coefficients;

symbol de-interleaving means for de-interleaving the symbols of the filtered encoded digital television signal to produce a de-interleaved digital television signal;

decoder means for decoding the de-interleaved digital television signal.

8. A television receiver as claimed in claim 7, wherein the encoded digital television signal is a precoded encoded digital television signal, and said prediction filter operates on the transmitted signal.