Patent US5003397A successfully refreshed from Google Patents.
US5003397A
Expired / Lapsed
US
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Television receiver including a tuning circuit which comprises a frequency synthesis circuit
Assignee: US Philips Corp
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Filing: 1989-07-10
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Granted: 1991-03-26
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Expires: 2009-07-10
Abstract
Abstract In a television receiver including a frequency synthesis circuit (33) controlled by a phase detection circuit (21), in which an adjustable frequency divider (15) receives a tuning datum which is corrigible by means of an AFC circuit (119, 129), a synchronous video signal detector (57) with a reference signal oscillator (97) are used, while the AFC detector is a counter (119) which is coupled via a measuring gate (115) to an output (99) of the reference signal oscillator, and the measuring gate (115) is operatd by a measuring gate signal having an accurate periodicity being derived from a received television signal, so that a minimum possible number of terminals on an integrated circuit is sufficient.
Inventors
- 👤 Meye Wink
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:54
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/02; H03J7/04; H03J7/06; H03J7/065; H04; H04N; H04N5/00; H04N5/44; H04N5/50
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
177 words
A television receiver including a tuning circuit which comprises a frequency synthesis circuit in which the tuning of a tuning oscillator is obtained by means of a frequency divider which is adjustable by means of a tuning datum, said tuning datum being corrigible by means of a frequency detection circuit when receiving a television signal identified as being correct by an identification circuit, said frequency detection circuit being coupled to an output of an intermediate frequency amplifier, an input of which is coupled to an output of the tuning circuit, characterized in that the frequency detection circuit is a counter which is coupled at least via a measuring gate to an output of a reference signal oscillator which forms part of a phase-coupled loop coupled to an output of the intermediate frequency amplifier, an output of said reference signal oscillator being further coupled to a reference signal input of a synchronous video signal detector while the measuring gate is operable by means of a measuring gate signal synchronized with the line frequency of a received television signal.
Claim 2
Dependent Claim
177 words
A television receiver including a tuning circuit which comprises a frequency synthesis circuit in which the tuning of a tuning oscillator is obtained by means of a frequency divider which is adjustable by means of a tuning datum, said tuning datum being corrigible by means of a frequency detection circuit when receiving a television signal identified as being correct by an identification circuit, said frequency detection circuit being coupled to an output of an intermediate frequency amplifier, an input of which is coupled to an output of the tuning circuit, characterized in that the frequency detection circuit is a counter which is coupled at least via a measuring gate to an output of a reference signal oscillator which forms part of a phase-coupled loop coupled to an output of the intermediate frequency amplifier, an output of said reference signal oscillator being further coupled to a reference signal input of a synchronous video signal detector while the measuring gate is operable by means of a measuring gate signal synchronized with the line frequency of a received television signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-03-25 | 1994-09-24 | 1995-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-25 | 1998-09-24 | 1999-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-25 | 2002-09-24 | 2003-03-26 | $7700.00 | Window Closed / Lapsed |