US3813604A
Expired / Lapsed
US
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Digital discriminator
Assignee: CMC Electronics Inc
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Filing: 1972-10-04
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Granted: 1974-05-28
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Expires: 1992-10-04
Abstract
Abstract The disclosure relates to a phase and frequency discriminator which is especially adaptable to digital communication receiver systems. The discriminator consists of a duty cycle generator having two input terminals. Each one of the terminals is fed from a different pulse generator, and one of the pulse generators is activated by the input signal while the other is activated by the second input signal. One of the pulse generators activates the duty cycle generator while the other one deactivates it. Thus, the output of the duty cycle generator is a signal whose duty cycle is proportional to the phase relation between the two signals. In accordance with the disclosure, if the second signal is derived from a VCO whose input is controlled by the duty cycle, the second signal is brought into phase and frequency synchronism with the first signal.
Inventors
- 👤 G Denoncourt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:01
CPC Classifications
H; H04; H04L; H04L7/00; H04L7/02; H04L7/033; H03; H03D; H03D3/00; H03D3/02; H03D3/24; H03D3/241; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085; H03L7/095; H03L7/16; H03L7/18; H03L7/183; H03L7/191
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
598 words
A discriminator for detecting phase or frequency differences between a first signal at a first frequency and a second signal at a second frequency; and comprising a duty cycle generator having a first input terminal and a second input terminal; a first pulse generator having an input terminal and an output terminal; and a second pulse generator having an input terminal and an output terminal; the input terminal of said first pulse generator being adapted to receive said first signal, and the output terminal of said first pulse generator being connected to said first input terminal of said duty cycle generator; the input terminal of said second pulse generator being adapted to receive the inverse of said second signal, and the output terminal of said second pulse generator being connected to the second input terminal of said duty cycle generator; wherein said first pulse generator comprises a first D flip-flop having a D input terminal and a CP input terminal and a Q output terminal and a Q output terminal; and wherein said second pulse generator comprises a second D flip-flop having a D input terminal and a CP input terminal and a Q output terminal and a Q output terminal; the CP terminals of said D flip-flops comprising the input terminals of said pulse generators, the Q output terminals of said D flipflops comprising the output terminals of said D flip-flops; said generator being activated when a predetermined recurring portion of said first signal is applied at said input terminal of said first pulse generator; said generator being deactivated when a corresponding recurring portion of said inverted second signal is applied at said input terminal of said second pulse generator; whereby the output of said duty cycle generator is a signal whose duty cycle is proportional to the phase or frequency relation between said first and said second signals, and further comprising a quadrature detector adapted to detect phase differences greater than plus or minus 90*; said quadrature detector comprising a third D flip-flop having a D input terminal and a CP input terminal, and a Q output terminal and a Q output terminal, said quadrature detector further comprising a fourth D flip-flop comprising a D input terminal and a CP input terminal and a Q output terminal and a Q output terminal; said discriminator further comprising an oscillator for providing a third signal at a frequency n times the second frequency, where n is an integer number; phase shift means connected to the output of the oscillator to shift the phase of the third signal by 180*; frequency divider means having an input terminal and two output terminals, the input terminal of the frequency divider means being connected to said phase shift means, one of the output terminals of said frequency divider means providing said second signal, shifted by 180*, the other output terminal of said frequency divider means providing a signal at twice said second frequency; said one output terminal of said frequency divider means being applied to the D terminal of said third D flip-flop; the output of said other terminal of said frequency divider means being applied to the CP input terminal of said third D flip-flop; second phase shift means connected to the CP terminal of said fourth D flip-flop; said first input signal being applied to said second phase shift means; said Q terminal of said third D flipflop being connected to the D terminal of said fourth D flipflop; the Q output terminal of said fourth D flip-flop being connected to the D terminals of said first and second flip-flops.
Claim 2
Dependent Claim
598 words
A discriminator for detecting phase or frequency differences between a first signal at a first frequency and a second signal at a second frequency; and comprising a duty cycle generator having a first input terminal and a second input terminal; a first pulse generator having an input terminal and an output terminal; and a second pulse generator having an input terminal and an output terminal; the input terminal of said first pulse generator being adapted to receive said first signal, and the output terminal of said first pulse generator being connected to said first input terminal of said duty cycle generator; the input terminal of said second pulse generator being adapted to receive the inverse of said second signal, and the output terminal of said second pulse generator being connected to the second input terminal of said duty cycle generator; wherein said first pulse generator comprises a first D flip-flop having a D input terminal and a CP input terminal and a Q output terminal and a Q output terminal; and wherein said second pulse generator comprises a second D flip-flop having a D input terminal and a CP input terminal and a Q output terminal and a Q output terminal; the CP terminals of said D flip-flops comprising the input terminals of said pulse generators, the Q output terminals of said D flipflops comprising the output terminals of said D flip-flops; said generator being activated when a predetermined recurring portion of said first signal is applied at said input terminal of said first pulse generator; said generator being deactivated when a corresponding recurring portion of said inverted second signal is applied at said input terminal of said second pulse generator; whereby the output of said duty cycle generator is a signal whose duty cycle is proportional to the phase or frequency relation between said first and said second signals, and further comprising a quadrature detector adapted to detect phase differences greater than plus or minus 90*; said quadrature detector comprising a third D flip-flop having a D input terminal and a CP input terminal, and a Q output terminal and a Q output terminal, said quadrature detector further comprising a fourth D flip-flop comprising a D input terminal and a CP input terminal and a Q output terminal and a Q output terminal; said discriminator further comprising an oscillator for providing a third signal at a frequency n times the second frequency, where n is an integer number; phase shift means connected to the output of the oscillator to shift the phase of the third signal by 180*; frequency divider means having an input terminal and two output terminals, the input terminal of the frequency divider means being connected to said phase shift means, one of the output terminals of said frequency divider means providing said second signal, shifted by 180*, the other output terminal of said frequency divider means providing a signal at twice said second frequency; said one output terminal of said frequency divider means being applied to the D terminal of said third D flip-flop; the output of said other terminal of said frequency divider means being applied to the CP input terminal of said third D flip-flop; second phase shift means connected to the CP terminal of said fourth D flip-flop; said first input signal being applied to said second phase shift means; said Q terminal of said third D flipflop being connected to the D terminal of said fourth D flipflop; the Q output terminal of said fourth D flip-flop being connected to the D terminals of said first and second flip-flops.
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) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |