US3611040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for deriving a signal proportional to a change-function of phase angle
Assignee: English Electric Co Ltd
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Filing: 1970-04-27
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Granted: 1971-10-05
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Expires: 1990-04-27
Abstract
Abstract Apparatus for deriving an output signal proportional to a particular change-function of absolute phase angle of an alternating input signal comprises a phase comparator which generates the output signal as a result of comparison of the phase angle of the input signal with the phase angle of a signal from an oscillator. The phase angle of the oscillator output is controlled by a signal derived from an operational amplifier in response to the output signal.
Inventors
- 👤 John Desmond Ainsworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:04
CPC Classifications
G; G05; G05B; G05B11/00; G05B11/01; G05B11/06; G05B11/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
115 words
Apparatus for deriving an output signal proportional to a change-function of absolute phase angle phi of an alternating input signal, which change-function is substantially of the form f(p) K phi .pT1/(1+ pT1).pT2/(1+ pT2)...pTn/(1+ pTn) where K is a gain constant, T1- Tn are time constants and p is the differential operator d/dt, said apparatus including an oscillator which generates oscillations having a phase angle controlled by a control signal, circuit means having a predetermined time-function response characteristic, said circuit means being responsive to said output signal to generate said control siGnal, and phase comparator means arranged to generate said output signal by comparison of the phase angles of said oscillations and of said input signal.
Claim 2
Dependent Claim
115 words
Apparatus for deriving an output signal proportional to a change-function of absolute phase angle phi of an alternating input signal, which change-function is substantially of the form f(p) K phi .pT1/(1+ pT1).pT2/(1+ pT2)...pTn/(1+ pTn) where K is a gain constant, T1- Tn are time constants and p is the differential operator d/dt, said apparatus including an oscillator which generates oscillations having a phase angle controlled by a control signal, circuit means having a predetermined time-function response characteristic, said circuit means being responsive to said output signal to generate said control siGnal, and phase comparator means arranged to generate said output signal by comparison of the phase angles of said oscillations and of said input signal.
Claim 3
Dependent Claim
16 words
Apparatus as claimed in claim 1, in which said phase comparator means comprises a multiplier circuit.
Claim 4
Dependent Claim
70 words
Apparatus as claimed in claim 1, in which said input signal is a m-phase signal and said oscillations are m-phase oscillations, m being any positive integer, and in which said phase comparator means comprises m multiplier circuits each responsive to one phase of the input signal and to a corresponding phase of the oscillations, said output signal being proportional to the sum of m signals generated by the multiplier circuits.
Claim 5
Dependent Claim
60 words
Apparatus as claimed in claim 1, in which said oscillations are of square waveform, and in which the phase comparator means comprises electronic switch means which is operated by the square wave oscillations to produce said output signal having, for successive half-cycles of the oscillations, respectively, a zero value and a value proportional to the magnitude of said input signal.
Claim 6
Dependent Claim
50 words
Apparatus as claimed in claim 4, in which said input signals are m-phase signals and said oscillations are m-phase square waves, m being any positive integer, and in which the electronic switch means comprises m electronic switches, each switch being operated by a corresponding phase of the square wave oscillations.
Claim 7
Dependent Claim
54 words
Apparatus as claimed in claim 1, in which said input signal is transformed from a three-phase signal to a two-phase signal, and in which said oscillations are two-phase oscillations, the phase comparator means comprising two-phase comparator devices responsive, respectively, to one phase of the transformed input signal and to one phase of the oscillations.
Claim 8
Dependent Claim
20 words
Apparatus as claimed in claim 1, arranged in a circuit for damping electrical oscillations in an electrical power transmission system.
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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |