Patent US3947775A successfully refreshed from Google Patents.
US3947775A
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Phase and frequency comparator
Assignee: Thales SA
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Filing: 1974-04-30
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Granted: 1976-03-30
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Expires: 1994-04-30
Abstract
Abstract The comparator comprises a circuit for detecting the sign of the phase-shift of the reference signal relatively to the second signal for a predetermined phase of the latter. It delivers a corresponding binary phase difference signal. A second circuit selects those changes in values of the phase difference signal which occur for a phase of the reference signal comprised in a predetermined phase interval, and are thus surely representative of a change in the sign of the frequency difference.
Inventors
- 👤 Jean-Jacques Thiebaut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:40
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/22; H03K5/26
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
221 words
A phase and frequency comparator having first and second inputs for respectively receiving a reference signal of period T and a second signal, and comprising: a comparison circuit coupled to said first and second inputs, and comprising means for, each time said second signal has a predetermined phase φ o for which the amplitude of said second signal is zero, determining the sign of the phase-shift, measured between - π and + π , of said reference signal relatively to said second signal, and delivering to said output a phase-shift digital signal having one or the other of two values depending upon the sign of this phase-shift; and a second circuit coupled to said first input, and to said output of said comparison circuit, comprising comparison means and gating means for detecting those particular phase-shift digital signals which simultaneously fulfill the two following conditions (i) they differ in value from the preceding phase-shift digital signal and (ii) they occur while the phase of the reference signal is included in a limited phase interval comprising one and only one value for which the amplitude of the reference signal is zero, and delivering to said output of said second circuit a frequency difference signal, the value of which is equal to the value of the last detected one of said particular phase-shift signals.
Claim 2
Dependent Claim
221 words
A phase and frequency comparator having first and second inputs for respectively receiving a reference signal of period T and a second signal, and comprising: a comparison circuit coupled to said first and second inputs, and comprising means for, each time said second signal has a predetermined phase φ o for which the amplitude of said second signal is zero, determining the sign of the phase-shift, measured between - π and + π , of said reference signal relatively to said second signal, and delivering to said output a phase-shift digital signal having one or the other of two values depending upon the sign of this phase-shift; and a second circuit coupled to said first input, and to said output of said comparison circuit, comprising comparison means and gating means for detecting those particular phase-shift digital signals which simultaneously fulfill the two following conditions (i) they differ in value from the preceding phase-shift digital signal and (ii) they occur while the phase of the reference signal is included in a limited phase interval comprising one and only one value for which the amplitude of the reference signal is zero, and delivering to said output of said second circuit a frequency difference signal, the value of which is equal to the value of the last detected one of said particular phase-shift signals.
Claim 3
Dependent Claim
85 words
A phase and frequency comparator as claimed in claim 1, wherein said comparison circuit comprises a limiting circuit for converting said reference signal into an intermediate binary signal which changes state for the phases φ o and φ o + π of said reference signal, a pulse generator supplying a pulse every time the phase of second signal is φ o and a sampling circuit for sampling said intermediate binary signal by said pulse, the output of said sampling circuit delivering said phase-shift digital signal.
Claim 4
Dependent Claim
122 words
A phase and frequency comparator as claimed in claim 2, wherein said comparing means include a memory element for temporarily storing each phase-shift digital signal and means coupled to said sampling circuit and to said memory element for delivering a control signal upon the digital signal stored in said memory element differing from the digital signal being delivered by said sampling circuit, and said gating means include means for delaying said intermediate binary signal and means for gating said control signal by means of the delayed intermediate binary signal, said second circuit further comprising a further memory element and means for storing the signal delivered by said sampling circuit in said further memory element, upon said gating means delivering an output pulse.
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) | 1979-03-30 | 1979-09-29 | 1980-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-30 | 1983-09-29 | 1984-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-30 | 1987-09-29 | 1988-03-30 | $7700.00 | Window Closed / Lapsed |