CA2241638A1 - Ntsc video signal receivers with reduced sensitivity to interference from co-channel digital television signals - Google Patents
Ntsc video signal receivers with reduced sensitivity to interference from co-channel digital television signalsInfo
- Publication number
- CA2241638A1 CA2241638A1 CA002241638A CA2241638A CA2241638A1 CA 2241638 A1 CA2241638 A1 CA 2241638A1 CA 002241638 A CA002241638 A CA 002241638A CA 2241638 A CA2241638 A CA 2241638A CA 2241638 A1 CA2241638 A1 CA 2241638A1
- Authority
- CA
- Canada
- Prior art keywords
- signal
- video signal
- vsb
- video
- synchronous detection
- 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
- 230000035945 sensitivity Effects 0.000 title abstract 2
- 238000001514 detection method Methods 0.000 abstract 4
- 230000001360 synchronised effect Effects 0.000 abstract 4
- 238000001914 filtration Methods 0.000 abstract 2
- 230000002452 interceptive effect Effects 0.000 abstract 1
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)
- Picture Signal Circuits (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Television Systems (AREA)
Abstract
A video signal receiver with reduced sensitivity to interference from co-channel digital TV signals includes circuitry for selecting a vestigial sideband amplitude-modulation signal descriptive of a video signal, converting the selected VSB AM signal to an intermediate frequency signal, and amplifying the IF signal to provide an amplified IF signal. The VSB AM signal is selected from any single one of a plurality of channels which can contain co-channel interference from a digital television signal. The amplified IF signal is synchronously detected with respect to video carrier frequency for generating an in-phase synchronous detection response and for generating a quadrature-phase synchronous detection response. All frequency components of the quadrature-phase synchronous detection response above a prescribed frequency are phase shifted substantially 90° and are linearly combined with in-phase synchronous detection response for recovering lower frequency portions of the video signal, substantially free of artifacts from any co-channel interfering digital television signal. In some embodiments of the video signal receiver higher frequency portions of the video signal described in the full sideband of the VSB AM
signal, but not in its vestigial sideband, are recovered by synchronously detecting the VSB AM signal after selective filtering to remove the pilot carrier signal component of any co-channel digital TV signal. The selective filtering avoids any artifact of such pilot carrier signal being generated when recovering higher frequency portions of the video signal. The lower and the higher frequency portions of the video signal are combined to obtain a fullband video signal.
signal, but not in its vestigial sideband, are recovered by synchronously detecting the VSB AM signal after selective filtering to remove the pilot carrier signal component of any co-channel digital TV signal. The selective filtering avoids any artifact of such pilot carrier signal being generated when recovering higher frequency portions of the video signal. The lower and the higher frequency portions of the video signal are combined to obtain a fullband video signal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/882,541 US5786870A (en) | 1997-03-21 | 1997-06-25 | NTSC video signal receivers with reduced sensitivity to interference from co-channel digital television signals |
| US08/882,541 | 1997-06-25 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2241638A1 true CA2241638A1 (en) | 1998-12-25 |
| CA2241638C CA2241638C (en) | 2001-09-11 |
Family
ID=25380815
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002241638A Expired - Fee Related CA2241638C (en) | 1997-06-25 | 1998-06-23 | Ntsc video signal receivers with reduced sensitivity to interference from co-channel digital television signals |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP3279520B2 (en) |
| KR (1) | KR100274744B1 (en) |
| CA (1) | CA2241638C (en) |
-
1998
- 1998-06-23 CA CA002241638A patent/CA2241638C/en not_active Expired - Fee Related
- 1998-06-25 KR KR1019980024182A patent/KR100274744B1/en not_active IP Right Cessation
- 1998-06-25 JP JP17944898A patent/JP3279520B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH1175091A (en) | 1999-03-16 |
| CA2241638C (en) | 2001-09-11 |
| JP3279520B2 (en) | 2002-04-30 |
| KR19990007350A (en) | 1999-01-25 |
| KR100274744B1 (en) | 2000-12-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |