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US4281348A
Expired / Lapsed
US
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Television signal receiving apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1979-08-02
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Granted: 1981-07-28
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Expires: 1999-08-02
Abstract
Abstract In apparatus for receiving a television signal which is made by a frequency-modulation by a video signal, the improvement is that a band-pass filter provided in the receiver for selectively taking out selected television signal is designed in a manner to have a center frequency shifted from a frequency corresponding to the center level of the video signal to the side of another frequency corresponding to white-signal level, so that noises of the picture in small signal receiving is decreased.
Inventors
- 👤 Osamu Shizuya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:43
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/04; H04N7/045
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
126 words
In an apparatus for receiving an FM television signal, the carrier wave thereof being frequency-modulated by a video signal including a synchronizing component and a video component with an amplitude larger than that of said synchronizing component, said apparatus comprising a band-pass filter for selectively taking out said FM television signal with a pass band width corresponding to one channel and an FM detector for reproducing said video signal by FM-detecting said FM television signal taken out from said band-pass filter, the improvement is that the center frequency of the pass band of said band-pass filter is set to be a frequency shifted from the center frequency of said FM television signal to the side of an instantaneous frequency modulated by a white level video signal.
Claim 2
Dependent Claim
126 words
In an apparatus for receiving an FM television signal, the carrier wave thereof being frequency-modulated by a video signal including a synchronizing component and a video component with an amplitude larger than that of said synchronizing component, said apparatus comprising a band-pass filter for selectively taking out said FM television signal with a pass band width corresponding to one channel and an FM detector for reproducing said video signal by FM-detecting said FM television signal taken out from said band-pass filter, the improvement is that the center frequency of the pass band of said band-pass filter is set to be a frequency shifted from the center frequency of said FM television signal to the side of an instantaneous frequency modulated by a white level video signal.
Claim 3
Dependent Claim
39 words
The apparatus of claim 1, wherein said band-pass filter comprises resonance circuits containing variable capacitance elements, and a control circuit for impressing a voltage responding to the intensity of the input FM television signal on said variable capacitance elements.
Claim 4
Dependent Claim
32 words
An apparatus in accordance with claim 1, characterized by further comprising a frequency converter containing a local oscillator, the oscillation frequency thereof being adjusted by intensity of the input FM television signal.
Claim 5
Dependent Claim
36 words
The apparatus of claim 3, wherein said local oscillator comprises variable capacitance elements, and a control circuit for impressing a voltage responding to the intensity of the input FM television signal on said variable capacitance elements.
Claim 6
Dependent Claim
51 words
The apparatus of claim 3, wherein said band-pass filter comprises resonance circuits containing variable capacitance elements, and said local oscillator comprises variable capacitance elements, and the apparatus further comprises a control circuit for impressing control voltages responding to the intensity of the input FM television signal on said variable capacitance elements.
Claim 7
Dependent Claim
45 words
The apparatus of claim 1, 2, 3, 4 or 5 wherein a maximum frequency shift of said frequency shifted from the center frequency of said FM television signal is selected to be about 3/14×a, where "a" is the maximum frequency deviation of said video signal.
References Cited (Backward Citations)
US2315050A
Cited
US3921077A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-07-27 | 1985-01-26 | 1985-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-27 | 1989-01-26 | 1989-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-27 | 1993-01-26 | 1993-07-28 | $7700.00 | Window Closed / Lapsed |