US3777268A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Degradation detection in a pcm system
Assignee: GPT INTERNATIONAL Ltd
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Filing: 1971-09-27
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Granted: 1973-12-04
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Expires: 1991-09-27
Abstract
Abstract An arrangement for detecting the degradation of a received PCM signal before it becomes bad enough to cause serious errors. Ancillary threshold detectors operate at levels on either side of the basic threshold. A falling signal level or rising noise level causes a received pulse to fall in the range between the ancillary levels, producing a warning signal to indicate a degraded signal. As described, the warning signals are integrated over a period of time to produce a time average. The arrangement is useful in repeaters of a radio relay system.
Inventors
- 👤 D Cleobury
- 👤 B Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:54
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/20; H04L27/00; H04L27/18; H04L27/22
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
162 words
A pulse-discriminator circuit, for use in a P.C.M. system, comprising: means for deriving an input signal from a transmission path; a first output path; means defining a first reference level; and threshold comparator means responsive to said input signal for comparing the amplitude of said input signal with said first reference level to produce an output pulse on said first output path in the event of the amplitude of said input signal exceeding said first reference level; characterized by signal degradation detection means comprising: means for defining second and third reference levels constituting limits of a restricted range of values that includes said first reference level; a second output path; and window comparatOr means responsive to said input signal for comparing the amplitude of said input signal with said second and third reference levels to produce an output pulse on said second output path if and only if the amplitude of said input signal falls between said second and third reference levels.
Claim 2
Dependent Claim
162 words
A pulse-discriminator circuit, for use in a P.C.M. system, comprising: means for deriving an input signal from a transmission path; a first output path; means defining a first reference level; and threshold comparator means responsive to said input signal for comparing the amplitude of said input signal with said first reference level to produce an output pulse on said first output path in the event of the amplitude of said input signal exceeding said first reference level; characterized by signal degradation detection means comprising: means for defining second and third reference levels constituting limits of a restricted range of values that includes said first reference level; a second output path; and window comparatOr means responsive to said input signal for comparing the amplitude of said input signal with said second and third reference levels to produce an output pulse on said second output path if and only if the amplitude of said input signal falls between said second and third reference levels.
Claim 3
Dependent Claim
89 words
A circuit according to claim 1 further including: means for deriving periodic timing pulses from said transmission path; first gating means responsive to said timing pulses for permitting a said output pulse from said threshold comparator means to be applied to said first output path only when a said timing pulse is present; and second gating means responsive to said timing pulses for permitting a said output pulse from said window comparator means to be applied to said second output path only when a said timing pulse is present.
Claim 4
Dependent Claim
32 words
A circuit according to claim 2 wherein said means for deriving said input signal comprises a phase demodulator means, and said means for deriving said timing pulses comprises an amplitude demodulator means.
Claim 5
Dependent Claim
32 words
A circuit according to claim 1 wherein said window comparator means comprises two further threshold comparator means for respectively comparing the amplitude of said input signal with said second and third levels.
Claim 6
Dependent Claim
52 words
A circuit according to claim 1 wherein said means for defining said first reference level comprises means responsive to said input signal for detecting a peak value of the amplitude of said input signal, and voltage divider means for producing a reference voltage equal to a predetermined fraction of said peak value.
Claim 7
Dependent Claim
12 words
A circuit according to claim 5 wherein said predetermined fraction is one-half.
Claim 8
Dependent Claim
54 words
A circuit according to claim 1 wherein said means for defining said second and third reference levels comprises means responsive to said input signal for detecting a peak value of the amplitude of said input signal, and voltage divider means for producing two reference voltages equal to respective predetermined fractions of said peak value.
Claim 9
Dependent Claim
15 words
A circuit according to claim 7 wherein said predetermined fractions are one-quarter and three-quarters respectively.
Claim 10
Dependent Claim
42 words
A circuit according to claim 1 wherein said signal degradation detection means further includes an integrator means connected to said second output path for producing a time average value for the rate of production of output pulses on said second output path.
Claim 11
Dependent Claim
20 words
A circuit according to claim 1 wherein said first reference level lies mid-way between said second and third reference levels.
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) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |