CA2241408A1 - Using special ntsc receiver to detect when co-channel interfering ntsc signal accompanies a digital tv signal - Google Patents
Using special ntsc receiver to detect when co-channel interfering ntsc signal accompanies a digital tv signalInfo
- Publication number
- CA2241408A1 CA2241408A1 CA002241408A CA2241408A CA2241408A1 CA 2241408 A1 CA2241408 A1 CA 2241408A1 CA 002241408 A CA002241408 A CA 002241408A CA 2241408 A CA2241408 A CA 2241408A CA 2241408 A1 CA2241408 A1 CA 2241408A1
- Authority
- CA
- Canada
- Prior art keywords
- signal
- digital television
- ntsc
- channel interfering
- television signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/14—Picture signal circuitry for video frequency region
- H04N5/21—Circuitry for suppressing or minimising disturbance, e.g. moiré or halo
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/455—Demodulation-circuits
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Noise Elimination (AREA)
- Television Receiver Circuits (AREA)
- Color Television Systems (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Picture Signal Circuits (AREA)
Abstract
A method for detecting when a digital television signal is accompanied by co-channel interfering NTSC signal of substantial amplitude is described for use in a digital television receiver. The video portion of any co-channel interfering NTSC
signal is synchrodyned to baseband, for generating an in-phase demodulation result including first artifacts of the digital television signal, and for generating aquadrature-phase demodulation result including second artifacts of the digital television signal.
The quadrature-phase demodulation results are phase shifted by 90° at frequencies in a prescribed frequency range before being linearly combined with the in-phase quadrature-phase demodulation results, to generate a linear combining result substantially free of the first and second artifacts of the digital television signal in the prescribed frequency range. An indication that the digital television signal is accompanied by co-channel interfering NTSC signal of substantial amplitude is generated by detecting whenever the amplitude of the linear combining result exceeds a prescribed value.
signal is synchrodyned to baseband, for generating an in-phase demodulation result including first artifacts of the digital television signal, and for generating aquadrature-phase demodulation result including second artifacts of the digital television signal.
The quadrature-phase demodulation results are phase shifted by 90° at frequencies in a prescribed frequency range before being linearly combined with the in-phase quadrature-phase demodulation results, to generate a linear combining result substantially free of the first and second artifacts of the digital television signal in the prescribed frequency range. An indication that the digital television signal is accompanied by co-channel interfering NTSC signal of substantial amplitude is generated by detecting whenever the amplitude of the linear combining result exceeds a prescribed value.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/882,540 US5852476A (en) | 1997-03-21 | 1997-06-25 | Using special NTSC receiver to detect when co-channel interfering NTSC signal accompanies a digital tv signal |
US08/882,540 | 1997-06-25 |
Publications (2)
Publication Number | Publication Date |
---|---|
CA2241408A1 true CA2241408A1 (en) | 1998-12-25 |
CA2241408C CA2241408C (en) | 2002-04-09 |
Family
ID=25380813
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002241408A Expired - Fee Related CA2241408C (en) | 1997-06-25 | 1998-06-23 | Using special ntsc receiver to detect when co-channel interfering ntsc signal accompanies a digital tv signal |
Country Status (3)
Country | Link |
---|---|
JP (1) | JP3576816B2 (en) |
KR (1) | KR100274743B1 (en) |
CA (1) | CA2241408C (en) |
-
1998
- 1998-06-23 CA CA002241408A patent/CA2241408C/en not_active Expired - Fee Related
- 1998-06-25 KR KR1019980024181A patent/KR100274743B1/en not_active IP Right Cessation
- 1998-06-25 JP JP17944798A patent/JP3576816B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH1175134A (en) | 1999-03-16 |
JP3576816B2 (en) | 2004-10-13 |
CA2241408C (en) | 2002-04-09 |
KR100274743B1 (en) | 2000-12-15 |
KR19990007349A (en) | 1999-01-25 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request | ||
MKLA | Lapsed | ||
MKLA | Lapsed |
Effective date: 20100623 |