US3812289A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Television receiver using synchronous video detection
Assignee: RCA Licensing Corp
•
Filing: 1972-11-06
•
Granted: 1974-05-21
•
Expires: 1992-11-06
Abstract
Abstract Synchronous video detection in a television receiver provides increased detection linearity and better signal-to-noise ratio for weak signals than does envelope video detection. Impulse noise, which produces generally unobtrusive black-going noise in a kinescope picture produced in accordance with a video signal recovered by envelope detection, conventionally produces obtrusive white-going noise as well in a picture produced in accordance with a video signal recovered by synchronous detection. Impulse noise detected by an auxiliary video detector responsive to the video i-f envelope provides a blanking signal to remove obtrusive white noise from the output signal of a synchronous video detector.
Inventors
- 👤 Jack Avins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:40
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/21; H04N5/44; H04N5/455
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
197 words
A detector for amplitude modulated signals comprising: a source of carrier waves bearing intelligence encoded in amplitude modulation thereof accompanied by impulse noise; a synchronous amplitude modulation detector having an input circuit coupled to said source, having an output circuit providing first recovered intelligence, and being responsive to impulse noise to provide from its said output circuit a first spurious signal at least portions of which are in a first polarity as referred to that of said first recovered intelligence, an envelope amplitude modulation detector having an input circuit coupled to said source, having an output circuit providing second recovered intelligence and being responsive to impulse noise to provide from its output circuit a second spurious signal which is in a second polarity as referred to that of said second recovered intelligence, said second polarity being opposite to said first polarity; utilization means for said first recovered intelligence; and means selectively coupling said output circuit of said synchronous detector to said utilization means responsive to whether said second spurious signal exceeds in said second polarity a predetermined threshold level respectively to not provide coupling and to provide coupling of said first recovered intelligence to said utilization means.
Claim 2
Dependent Claim
197 words
A detector for amplitude modulated signals comprising: a source of carrier waves bearing intelligence encoded in amplitude modulation thereof accompanied by impulse noise; a synchronous amplitude modulation detector having an input circuit coupled to said source, having an output circuit providing first recovered intelligence, and being responsive to impulse noise to provide from its said output circuit a first spurious signal at least portions of which are in a first polarity as referred to that of said first recovered intelligence, an envelope amplitude modulation detector having an input circuit coupled to said source, having an output circuit providing second recovered intelligence and being responsive to impulse noise to provide from its output circuit a second spurious signal which is in a second polarity as referred to that of said second recovered intelligence, said second polarity being opposite to said first polarity; utilization means for said first recovered intelligence; and means selectively coupling said output circuit of said synchronous detector to said utilization means responsive to whether said second spurious signal exceeds in said second polarity a predetermined threshold level respectively to not provide coupling and to provide coupling of said first recovered intelligence to said utilization means.
Claim 3
Dependent Claim
52 words
A detector as defined in claim 1 wherein: said source of carrier waves bearing intelligence provides video intermediate frequency signals to said synchronous and said envelope amplitude modulation detectors which respond with respective detected video signals, each including synchronizing pulse information and said utilization means further comprises a synchronizing signal separator circuit.
Claim 4
Dependent Claim
41 words
A detector as defined in claim 1 wherein: said source of carrier waves bearing intelligence further provides a frequency-modulated component signal and said utilization means further comprises means for detecting that portion of said intelligence borne by said frequency-modulated component signal.
Claim 5
Dependent Claim
93 words
In a television receiver including a synchronous video detector detecting composite video signal carrier waves to provide video signals for application to video processing circuitry and to sync separation means, the improvement comprising: auxiliary detector means to provide a blanking signal in response to excursions of the envelope of said composite video signal carrier waves which exceed a threshold value and blanking means interposed between said synchronous viDeo detector and said video processing circuitry and responsive to said blanking signal to interrupt said application of said video signals to said video processing circuitry.
Claim 6
Dependent Claim
93 words
In a television receiver including a synchronous video detector detecting composite video signal carrier waves to provide video signals for application to video processing circuitry and to sync separation means, the improvement comprising: auxiliary detector means to provide a blanking signal in response to excursions of the envelope of said composite video signal carrier waves which exceed a threshold value and blanking means interposed between said synchronous viDeo detector and said video processing circuitry and responsive to said blanking signal to interrupt said application of said video signals to said video processing circuitry.
Claim 7
Dependent Claim
91 words
The improvement defined in claim 4 wherein: said auxiliary detector means comprises an envelope detector having input terminals and output terminals, said composite video signal carrier waves being coupled to said input terminals; a threshold detector having input and output terminals, said threshold detector input terminals being direct coupled to said envelope detector output terminals, said threshold detector output terminals being coupled to said blanking means to furnish said blanking signal; and sound recovery circuitry for said television receiver having an input signal circuit coupled to said envelope detector output terminals.
Claim 8
Dependent Claim
100 words
The improvement defined in claim 4 wherein said blanking means comprises: a source of predetermined video level and an electrically controlled selector means having a first and a second sets of input terminals respectively coupled to said synchronous video detector and to said source of predetermined video level, having control terminals connected to receive said blanking signal and having output terminals coupled to said video processing circuitry and selectively coupled to said first set of input terminals in the absence of said blanking signal and coupled to said second set of input terminals in the presence of said blanking signal.
Claim 9
Dependent Claim
56 words
The improvement defined in claim 6 wherein: said predetermined video level is no blacker-than-black level with respect to said video signals for application to video processing circuitry and said blanking means is interposed between said synchronous video detector and said sync separation means as well as between said synchronous video detector and said video processing circuitry.
Claim 10
Dependent Claim
43 words
The improvement defined in claim 4 wherein said blanking means comprises: a source of predetermined video level and keyed clamping means for clamping said video signals for application to video processing circuitry to said predetermined video level in response to said blanking signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |