US3641447A
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Phase shift detector
Assignee: International Standard Electric Corp
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Filing: 1970-02-25
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Granted: 1972-02-08
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Expires: 1990-02-25
Abstract
Abstract An apparatus for measuring the phase of an input signal utilizing cross-correlation techniques. In a first channel, the input signal is digitally compared with a reference pulse train having a pulse density distribution which approximates a sign wave and is then integrated. In a second channel, the input signal is digitally compared with a pulse train signal whose pulse density distribution approximates a cosine wave and is then integrated. The first and second channel integrators are cross coupled to form a harmonic oscillator. A digital counter provides a measure of the time elapsed before the oscillator signal reaches a zero phase. This measurement is proportional to the phase of the original input signal.
Inventors
- 👤 Brian R Gaines
- 👤 Raymond A Shemer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:55
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; G01S3/14; G01S3/52
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
230 words
A phase shift measuring apparatus for determining the phase of a given frequency component of an input signal with respect to a reference signal which comprises: a source of clock pulses having a repetition frequency signal to a multiple of the given frequency; means for deriving a first pulse train signal from said clock pulse; means for deriving a second pulse train signal from said clock pulse; means for gating the input with each of said first and second pulse train signals such that the gated outputs represent the products of the input signal with each of said first and second pulse trains having fundamental sinusoidal frequency components which are equal in frequency to the given frequency, and are in phase quadrature with each other and bear a predetermined phase relationship with the reference signal; a first integrator; a second integrator; means for coupling said gated outputs to said first and second integrators respectively for a predetermined period of time; means for cross coupling the inputs and outputs of said first and second integrators to form a harmonic oscillator; a local pulse generator; a phase detector coupled to the outputs of said first and second integrators; and a counter driven by said local pulse generator and coupled to the output of said zero phase detector for measuring phase shift by counting elapsed time before the oscillator signal reaches zero phase.
Claim 2
Dependent Claim
230 words
A phase shift measuring apparatus for determining the phase of a given frequency component of an input signal with respect to a reference signal which comprises: a source of clock pulses having a repetition frequency signal to a multiple of the given frequency; means for deriving a first pulse train signal from said clock pulse; means for deriving a second pulse train signal from said clock pulse; means for gating the input with each of said first and second pulse train signals such that the gated outputs represent the products of the input signal with each of said first and second pulse trains having fundamental sinusoidal frequency components which are equal in frequency to the given frequency, and are in phase quadrature with each other and bear a predetermined phase relationship with the reference signal; a first integrator; a second integrator; means for coupling said gated outputs to said first and second integrators respectively for a predetermined period of time; means for cross coupling the inputs and outputs of said first and second integrators to form a harmonic oscillator; a local pulse generator; a phase detector coupled to the outputs of said first and second integrators; and a counter driven by said local pulse generator and coupled to the output of said zero phase detector for measuring phase shift by counting elapsed time before the oscillator signal reaches zero phase.
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) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |