US4095259A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Video signal converting system having quantization noise reduction
Assignee: Sony Corp
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Filing: 1976-06-21
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Granted: 1978-06-13
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Expires: 1996-06-21
Abstract
Abstract In a system in which a video signal is converted into a digitized signal, clamp levels thereof at every horizontal synchronizing interval are randomly shifted before conversion, whereby quantization noise signals can be scattered on a displayed image by reclamping after a reconversion of the signal.
Inventors
- 👤 Kiyoshi Sawagata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:00
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/90
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
203 words
A video signal converting system comprising: circuit means for receiving an analog video signal that includes a DC level and having respective information intervals; level shifting means connected to said circuit means to shift the DC level of said video signal to different random values at equally spaced intervals, said level shifting means comprising random noise generating means for generating a noise signal having a level which changes randomly from one information interval to the next and which remains constant throughout each respective information interval, and means for changing the DC level of said video signal in successive information intervals with said noise signal such that said video signal DC level is constant throughout a respective information interval and then changes in the next successive interval; digitizing means connected to said level shifting means to receive therefrom the analog video signal with the shifted DC level; signal utilization means for receiving and utilizing the digitized level-shifted video signal from said digitizing means; converting means connected to said signal utilization means for receiving and converting the digitized video signal to an analog level-shifted video signal; and clamping means connected to said converting means to restore said analog video signal to its original DC level.
Claim 2
Dependent Claim
203 words
A video signal converting system comprising: circuit means for receiving an analog video signal that includes a DC level and having respective information intervals; level shifting means connected to said circuit means to shift the DC level of said video signal to different random values at equally spaced intervals, said level shifting means comprising random noise generating means for generating a noise signal having a level which changes randomly from one information interval to the next and which remains constant throughout each respective information interval, and means for changing the DC level of said video signal in successive information intervals with said noise signal such that said video signal DC level is constant throughout a respective information interval and then changes in the next successive interval; digitizing means connected to said level shifting means to receive therefrom the analog video signal with the shifted DC level; signal utilization means for receiving and utilizing the digitized level-shifted video signal from said digitizing means; converting means connected to said signal utilization means for receiving and converting the digitized video signal to an analog level-shifted video signal; and clamping means connected to said converting means to restore said analog video signal to its original DC level.
Claim 3
Dependent Claim
45 words
A video signal converting system as claimed in claim 1 in which said level shifting means includes a clamping circuit, the clamp level of said clamping circuit being shifted at each of the information intervals in accordance with the level of said generated noise signal.
Claim 4
Dependent Claim
59 words
A video signal converting system as claimed in claim 1 in which the analog video signal received by said circuit means is DC restored to a fixed voltage, and said level shifting means includes an adding circuit connected to said random noise generating means and to said circuit means to add said generated noise signal to the video signal.
Claim 5
Dependent Claim
57 words
A video signal converting system as claimed in claim 1 wherein said converting means is a digital to analog converter; to reconvert the digitized signal to an analog video signal including synchronizing signals separating successive information intervals; and said clamping means clamps the reconverted analog video signal to a fixed voltage level at the successive information intervals.
Claim 6
Dependent Claim
48 words
A video signal converting system as claimed in claim 4 comprising a horizontal synchronizing signal separating circuit connected to said digital to analog converter to receive the reconverted analog video signal therefrom and connected to said clamping circuit to supply separated horizontal synchronizing signals thereto as clamping signals.
Claim 7
Dependent Claim
154 words
A video signal converting system comprising: circuit means for receiving an analog video signal that includes a DC level; setting means connected to said circuit means to set the DC level at different values at the horizontal synchronizing signal intervals of the video signal, said setting means comprising a horizontal synchronizing signal separator circuit connected to said circuit means to receive the video signal therefrom, a random noise generator to generate a noise signal having a random value to be combined with the video signal at each of the horizontal synchronizing signal intervals of the video signal, and a horizontal interval sample-and-hold circuit connected to said random noise generator to receive the noise signal therefrom and connected to said separator circuit to sample the noise signal at every horizontal synchronizing signal interval; and digitizing means connected to said setting means to receive therefrom the analog video signal with the DC level at different values.
Claim 8
Dependent Claim
154 words
A video signal converting system comprising: circuit means for receiving an analog video signal that includes a DC level; setting means connected to said circuit means to set the DC level at different values at the horizontal synchronizing signal intervals of the video signal, said setting means comprising a horizontal synchronizing signal separator circuit connected to said circuit means to receive the video signal therefrom, a random noise generator to generate a noise signal having a random value to be combined with the video signal at each of the horizontal synchronizing signal intervals of the video signal, and a horizontal interval sample-and-hold circuit connected to said random noise generator to receive the noise signal therefrom and connected to said separator circuit to sample the noise signal at every horizontal synchronizing signal interval; and digitizing means connected to said setting means to receive therefrom the analog video signal with the DC level at different values.
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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) | 1981-06-12 | 1981-12-12 | 1982-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-12 | 1985-12-12 | 1986-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-12 | 1989-12-12 | 1990-06-13 | $7700.00 | Window Closed / Lapsed |