US3750029A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Television receiver
Assignee: US Philips Corp
•
Filing: 1971-11-02
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Granted: 1973-07-31
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Expires: 1991-11-02
Abstract
Abstract In a television receiver employing a synchronous demodulator for the intermediate frequency signal and an intermediate frequency picture carrier oscillator coupled thereto a frequency control signal is obtained from a phase detector active on the intermediate picture frequency and is applied via a highpass filter to the intermediate frequency picture carrier oscillator and via a lowpass filter to the oscillator of the mixer stage of the receiver.
Inventors
- 👤 N Baars
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:50
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/455; H04N5/50
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
120 words
A circuit for receiving a signal having a carrier, said circuit comprising a mixer having a first input adapted to receive said signal, a second input, and an output means for providing said signal at an intermediate frequency; an oscillator having an output coupled to said mixer second input and a frequency control input; a phase detector having a first input coupled to said mixer output, a second input, and an output coupled to said oscillator control input; means for generating a signal having a frequency equal the carrier intermediate frequency having an output coupled to said detector second input and a frequency control input; and a high pass filter coupled between said detector output and said generator control input.
Claim 2
Dependent Claim
120 words
A circuit for receiving a signal having a carrier, said circuit comprising a mixer having a first input adapted to receive said signal, a second input, and an output means for providing said signal at an intermediate frequency; an oscillator having an output coupled to said mixer second input and a frequency control input; a phase detector having a first input coupled to said mixer output, a second input, and an output coupled to said oscillator control input; means for generating a signal having a frequency equal the carrier intermediate frequency having an output coupled to said detector second input and a frequency control input; and a high pass filter coupled between said detector output and said generator control input.
Claim 3
Dependent Claim
23 words
A circuit as claimed in claim 5 further comprising a low pass filter coupled between said detector output and said oscillator control input.
Claim 4
Dependent Claim
16 words
A circuit as claimed in claim 2 wherein said filters have substantially equal cut off frequencies.
Claim 5
Dependent Claim
16 words
A circuit as claimed in claim 3 wherein said cut off frequencies equal one hundred Hertz.
Claim 6
Dependent Claim
21 words
A circuit as claimed in claim 2 wherein said low and high pass filters each comprise resistoR-capacitor integrator and differentiator respectively.
Claim 7
Dependent Claim
17 words
A circuit as claimed in claim 5 wherein said differentiator and integrator have substantially equal time constants.
Claim 8
Dependent Claim
41 words
A circuit as claimed in claim 1 wherein said oscillator, mixer, and detector comprise a first frequency control loop; said generator, detector, and high pass filter comprise a second frequency control loop; the loop gains of said loops being substantially equal.
Claim 9
Dependent Claim
23 words
A circuit as claimed in claim 1 further comprising an intermediate frequency amplifier coupled between said mixer output and said detector first input.
Claim 10
Dependent Claim
38 words
A circuit as claimed in claim 1 further comprising a synchronous detector having a first input coupled to said mixer output, and second input coupled to said generator output, and an output means for providing a detected signal.
References Cited (Backward Citations)
US3189825A
Cited
US3428900A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |