US4241362A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for increasing a signal slope of a periodically occurring signal mainly near a reference level
Assignee: US Philips Corp
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Filing: 1978-11-14
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Granted: 1980-12-23
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Expires: 1998-11-14
Abstract
Abstract A circuit for increasing, mainly near a reference level, a signal slope of a periodically occurring signal, particularly at the black level of a television picture signal. To this end the gamma-corrected and limited luminance signal is applied in a color television camera to a first input of a differential amplifier, a second input of which is connected to a reference potential, the amplifier output being connected via a signal limiting circuit arranged in series with a first and a second resistor, respectively, to the first amplifier input and the reference potential, respectively. The junction of the resistors supplies the correction signal which increases the signal slope but does not effect either the black level or the peak-white value.
Inventors
- 👤 Nicolaas J. L. van der Valk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:46
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/10; H04N23/13; H04N9/00; H04N9/64; H04N9/68; H04N9/69
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
134 words
A circuit for increasing, mainly near a reference level, a signal slope of a periodically occurring signal, wherein the circuit comprises a differential amplifier provided with a first and a second input to which the supply of the signal to be processed and a reference potential, respectively, and supplied, and an output; a first signal limiting circuit connected to said amplifier output; a first and a second resistor arranged serially and connected at the junction thereof to said first signal limiting circuit, said first and second resistors being connected respectively to the first amplifier input and the reference potential; and a superposition stage having a first input connected to said junction and a second input for receiving the signal to be processed, and an output for supplying the signal with the increased signal slope.
Claim 2
Dependent Claim
134 words
A circuit for increasing, mainly near a reference level, a signal slope of a periodically occurring signal, wherein the circuit comprises a differential amplifier provided with a first and a second input to which the supply of the signal to be processed and a reference potential, respectively, and supplied, and an output; a first signal limiting circuit connected to said amplifier output; a first and a second resistor arranged serially and connected at the junction thereof to said first signal limiting circuit, said first and second resistors being connected respectively to the first amplifier input and the reference potential; and a superposition stage having a first input connected to said junction and a second input for receiving the signal to be processed, and an output for supplying the signal with the increased signal slope.
Claim 3
Dependent Claim
43 words
A circuit as claimed in claim 1, wherein the first input of the differential amplifier is coupled to the output of a second signal limiting circuit for obtaining a peak value, fixed relative to the reference level, in the signal to be processed.
Claim 4
Dependent Claim
40 words
A circuit as claimed in claim 1 or 2, wherein the first signal limiting circuit comprises two diodes, which are arranged in series with opposite pass directions, and a variable resistor connecting the diode junction to a power supply terminal.
Claim 5
Dependent Claim
22 words
A circuit as claimed in claim 3 wherein the circuit further comprises an on-off switch arranged in series with the differential amplifier.
Claim 6
Dependent Claim
53 words
A circuit as claimed in claim 1 suitable for use in a color television camera, wherein the circuit is present in a luminance channel subsequent to a matrix circuit, inputs of the matrix circuit being connected to outputs of series arrangements, each consisting of a gamma correction circuit and a signal limiting circuit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |