Patent US4642693A successfully refreshed from Google Patents.
US4642693A
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Television video signal A/D converter apparatus
Assignee: Casio Computer Co Ltd
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Filing: 1985-05-13
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Granted: 1987-02-10
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Expires: 2005-05-13
Abstract
Abstract A television video signal A/D converter apparatus in a liquid crystal television receiver has an A/D converter for A/D converting a television video signal. Upper and lower reference potentials for determining an operating voltage amplitude are supplied to the A/D converter from a reference potential generator. The upper and lower reference potentials are divided at a given ratio by a resistor so as to fix an average potential of the television video signal at a constant value using the potential at the dividing point as a bias potential, and thereafter the television video signal is supplied to the A/D converter.
Inventors
- 👤 Takahiro Fuse
- 👤 Masao Kawamura
- 👤 Koji Yamagishi
- 👤 Kazuyuki Odachi
- 👤 Haruo Ono
- 👤 Masaharu Kizaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:40
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/57; H04N3/00; H04N3/10; H04N3/12; H04N3/127; H03; H03M; H03M1/00; H03M1/12; H03M1/34; H03M1/36; H03M1/361; H03M1/362
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
117 words
A television video signal A/D converter apparatus in a liquid crystal television receiver, comprising: A/D converting means for A/D converting a television video signal; reference potential generating means connected to said A/D converting means and comprising means for supplying a predetermined upper reference potential (VH) and means for supplying a predetermined lower reference potential (VL); and high-pass filter means for dividing the upper and lower reference potentials at a given ratio by a resistor so as to supply to said A/D converting means the input television video signal having a potential level which is fixed at a constant value using the potential at the dividing point of the upper and lower reference potentials as a bias potential.
Claim 2
Dependent Claim
117 words
A television video signal A/D converter apparatus in a liquid crystal television receiver, comprising: A/D converting means for A/D converting a television video signal; reference potential generating means connected to said A/D converting means and comprising means for supplying a predetermined upper reference potential (VH) and means for supplying a predetermined lower reference potential (VL); and high-pass filter means for dividing the upper and lower reference potentials at a given ratio by a resistor so as to supply to said A/D converting means the input television video signal having a potential level which is fixed at a constant value using the potential at the dividing point of the upper and lower reference potentials as a bias potential.
Claim 3
Dependent Claim
39 words
An apparatus according to claim 1, wherein said upper and lower reference potential supplying means in said reference potential generating means respectively comprise resistors for adjusting the upper and lower reference potentials so as to determine operating voltage amplitudes.
Claim 4
Dependent Claim
19 words
An apparatus according to claim 1, wherein said upper and lower reference potential supplying means respectively comprise smoothing capacitors.
Claim 5
Dependent Claim
41 words
An apparatus according to claim 1, wherein said high-pass filter means comprises a capacitor for receiving the television video signal and resistor means, having a middle point to which said capacitor is connected, for dividing the upper and lower reference potentials.
Claim 6
Dependent Claim
27 words
An apparatus according to claim 1, wherein said A/D converting means comprises Red, Green and Blue A/D converting circuits for A/D converting a color television video signal.
Claim 7
Dependent Claim
50 words
An apparatus according to claim 5, wherein said A/D converting means have a color demodulating circuit for demodulating the television video signal into Red, Green and Blue color signals so as to supply the Red, Green and Blue color signals to said corresponding Red, Green and Blue A/D converting circuits.
Claim 8
Dependent Claim
18 words
An apparatus according to claim 6, wherein said color demodulation circuit has variable resistor means for adjusting contrast.
Claim 9
Dependent Claim
30 words
An apparatus according to claim 5, wherein at least two of said Red, Green and Blue A/D converting circuits have variable resistor means for adjusting contrast at input sides thereof.
References Cited (Backward Citations)
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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) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |