US4097697A
Expired / Lapsed
US
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Digital signal performance monitor
Assignee: Nortel Networks Ltd
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Filing: 1977-06-02
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Granted: 1978-06-27
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Expires: 1997-06-02
Abstract
Abstract A performance monitor for determining the error density of a digitally transmitted signal in which the magnitude of a d-c offset voltage applied to one regenerator is controlled in a feedback loop so as to maintain a constant error rate between the output of it and another regenerator; the magnitude of the voltage being a measure of the degradation of the received signal and hence its error density.
Inventors
- 👤 Stephen George Harman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:06
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/24; H04L1/241
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
115 words
In a performance monitor for a degraded digital signal, an error voltage output circuit comprising: regenerators for regenerating the degraded digital signal and the degraded digital signal offset against a d-c voltage; a comparator for detecting parity errors in the digital state between the two regenerated digital signals; a negative feedback circuit, responsive to the number of parity errors at the output of the comparator, for varying the magnitude of said d-c voltage to maintain a substantially constant error rate between the two regenerated digital signals; and output means for the d-c voltage; whereby the magnitude of the d-c voltage is a measure of the degradation of the digital signal and hence the error density.
Claim 2
Dependent Claim
115 words
In a performance monitor for a degraded digital signal, an error voltage output circuit comprising: regenerators for regenerating the degraded digital signal and the degraded digital signal offset against a d-c voltage; a comparator for detecting parity errors in the digital state between the two regenerated digital signals; a negative feedback circuit, responsive to the number of parity errors at the output of the comparator, for varying the magnitude of said d-c voltage to maintain a substantially constant error rate between the two regenerated digital signals; and output means for the d-c voltage; whereby the magnitude of the d-c voltage is a measure of the degradation of the digital signal and hence the error density.
Claim 3
Dependent Claim
132 words
In a performance monitor for a degraded binary signal, an error voltage output circuit comprising: a first regenerator for regenerating the degraded binary signal; a second regenerator for regenerating the degraded binary signal offset against a variable d-c voltage; a gate, for generating an output for each parity error in the binary states between the regenerated signals from the first and second regenerators; a negative feedback circuit responsive to said output of said gate for controlling the magnitude of the variable d-c voltage to maintain the rate of parity errors between the regenerated signals substantially constant; and output means for the d-c voltage; whereby the magnitude of the d-c voltage is a measure of the degradation of the binary signal and hence the number of decision errors generated by the first regenerator.
Claim 4
Dependent Claim
132 words
In a performance monitor for a degraded binary signal, an error voltage output circuit comprising: a first regenerator for regenerating the degraded binary signal; a second regenerator for regenerating the degraded binary signal offset against a variable d-c voltage; a gate, for generating an output for each parity error in the binary states between the regenerated signals from the first and second regenerators; a negative feedback circuit responsive to said output of said gate for controlling the magnitude of the variable d-c voltage to maintain the rate of parity errors between the regenerated signals substantially constant; and output means for the d-c voltage; whereby the magnitude of the d-c voltage is a measure of the degradation of the binary signal and hence the number of decision errors generated by the first regenerator.
Claim 5
Dependent Claim
48 words
A performance monitor as defined in claim 2 in which the negative feedback circuit includes a current generator; means for gating the current generator on in response to an output from said gate; means for integrating the output from the current generator to derive said variable d-c voltage.
Claim 6
Dependent Claim
48 words
A performance monitor as defined in claim 3 in which each of the regenerators is an overdriven differential amplifier having the degraded digital signal coupled directly between inputs of the first regenerator, and coupled in series with the variable d-c voltage between the inputs of the second regenerator.
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) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |