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Patent US4518927A successfully refreshed from Google Patents.
US4518927A
Expired / Lapsed
US
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Signal processing system comprising a signal source, a signal processing unit and connecting cables
Assignee: US Philips Corp
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Filing: 1983-06-23
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Granted: 1985-05-21
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Expires: 2003-06-23
Abstract
Abstract A signal processing system comprising a signal source (CAM), a signal processing unit (CPU) and connecting cables (CC1-CC5) having different lengths. A series circuit comprising a switchable signal attenuator (ATT), a low-noise, non-controlled signal amplifier (AMP2) and a AGC-signal amplifier (AMP1) is present to compensate for the variable cable losses. A change-over input (ST) of the signal attenuator (ATT) is coupled to a change-over circuit (ATS) which has a locking input (LT) and a measuring signal input (DT). The measuring signal input (TD) is coupled directly to a signal detection circuit (DET). A second output of the signal detection circuit is coupled to the locking input (LT), through a time signal generator (TSG). After a time delay of several dozen seconds, locking is effected, and the signal attenuator (ATT) can no longer switch-over during the normal signal processing operation and impermissible sudden signal amplitude changes are prevented.
Inventors
- 👤 Rudolf P. Koppe
- 👤 Hendrik Blom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:19
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H04; H04N; H04N5/00; H04N5/04; H04N5/06; H04N5/067; H04N5/073; H04N5/0733
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
182 words
A signal processing system which provides a substantially constant amplitude signal transmitted over a connecting cable selected from a plurality of connecting cables of different lengths of different losses, comprising: a series signal processing circuit which receives a signal from said selected cable which includes: a signal amplifier having automatic gain control, a low noise signal amplifier having a fixed gain, a switchable signal attenuator having a changeover input which selects and locks a different attenuation level in response to an applied signal a timing signal generator for generating a delay signal in response to an input signal; a signal detector connected to receive an output signal from said series circuit, and to supply an input signal to said timing signal generator; and a changeover circuit connected to receive a signal from said signal detector and said timing signal generator, said changeover circuit connected to said switchable signal attenuator changeover input, said series signal processing circuit providing a controlled amplitude signal when a selected attenuation level is locked by said delay signal after a time delay generated by said timing signal generator.
Claim 2
Dependent Claim
182 words
A signal processing system which provides a substantially constant amplitude signal transmitted over a connecting cable selected from a plurality of connecting cables of different lengths of different losses, comprising: a series signal processing circuit which receives a signal from said selected cable which includes: a signal amplifier having automatic gain control, a low noise signal amplifier having a fixed gain, a switchable signal attenuator having a changeover input which selects and locks a different attenuation level in response to an applied signal a timing signal generator for generating a delay signal in response to an input signal; a signal detector connected to receive an output signal from said series circuit, and to supply an input signal to said timing signal generator; and a changeover circuit connected to receive a signal from said signal detector and said timing signal generator, said changeover circuit connected to said switchable signal attenuator changeover input, said series signal processing circuit providing a controlled amplitude signal when a selected attenuation level is locked by said delay signal after a time delay generated by said timing signal generator.
Claim 3
Dependent Claim
24 words
The signal processing circuit of claim 1 wherein the gain of said signal amplifier having automatic gain control is controlled by said signal detector.
Claim 4
Dependent Claim
44 words
The signal processing circuit of claim 1 further comprising a hysteresis control means for switching over said attenuator at a different detected signal level during the detection of a decreasing signal provided by said series signal processing circuit than for an increasing signal level.
Claim 5
Dependent Claim
26 words
A signal processing system as claimed in claim 1, wherein said time delay signal for locking the signal attenuator has a duration of several dozen seconds.
Claim 6
Dependent Claim
110 words
A signal processing system as claimed in claim 1 or 4, wherein a maximum possible cable loss in the system is equal to C dB, and said switchable signal attenuator has a plurality of n attenuation positions, the control range of the signal amplifier having automatic gain control extending from zero to a value of at least (1/n) C dB, the gain factor of the low-noise signal amplifier is not greater than the value of (n-1)/n dB, and the switchable signal attenuator has n attenuation factors which sequentially are not greater than (n-1)/n C dB, (n-2)/n C dB, (n-3)/n C dB, the last attenuation factor being substantially equal to zero.
References Cited (Backward Citations)
FR2469829A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-20 | 1988-11-19 | 1989-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-20 | 1992-11-19 | 1993-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-20 | 1996-11-19 | 1997-05-21 | $7700.00 | Window Closed / Lapsed |