Patent US3753114A successfully refreshed from Google Patents.
US3753114A
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Method and apparatus for the recovery of synchronous carrier in a digital communication system
Assignee: CULBERTSON IND Inc
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Filing: 1971-12-02
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Granted: 1973-08-14
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Expires: 1991-12-02
Abstract
Abstract A carrier recovery and coherent detection system in a digital communication system having a quadrature or biphase PSK incoming signal, the incoming signal being divided and transmitted to a pair of radio frequency mixers, these mixers receiving their reference inputs from a voltage controlled oscillator in a phase lock loop, one of the reference signals being phase shifted relative to the other. The outputs of the two mixers are utilized to produce a phase error signal in the phase lock feedback loop to the VCO to synchronize the VCO with the carrier signal. The mixer outputs serve to indicate the proper digital symbol output.
Inventors
- 👤 C Burley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:23
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/227; H04L27/2271; H04L27/2273; H04L27/0014; H04L2027/0044; H04L2027/0046; H04L2027/0048; H04L2027/0053; H04L2027/0057; H04L2027/0063; H04L2027/0067
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
349 words
Apparatus for the recovery of synchronous carrier for coherent detection of a signal in a digital communication system, the incoming signal consisting of a series of successive time intervals of radio frequency signal, the phase of the radio frequency signal during each time interval being any one of a plurality of different phases, said apparatus comprising, means for splitting the incoming signal into two parts, a tunable radio frequency source of substantially the same frequency as said incoming signal, a first radio frequency mixer mixing one of said incoming signal parts with a reference radio frequency signal from said tunable radio frequency source to obtain a pair of output signals with sign dependent on the direction of the phase shift between the incoming signal and the reference signal and with amplitude dependent on the degree of phase shift between the incoming and reference signals, said two output signals having opposite signs, phase shifting means coupled to said radio frequency source for providing a second reference radio frequency signal in quadrature with said first reference signal, a second radio frequency mixer for mixing the second one of said incoming signal parts with said second reference signal to obtain a second pair of output signals with sign dependent on the direction of the phase shift between the incoming signal and the second reference signal and with amplitude dependent on the degree of phase shift between the incoming and second reference signals, said two second output signals having opposite signs, means coupled to said radio frequency mixers and responsive to differnet ones of said four mixer output signals operative to identify the possible phases of the incoming radio frequency signal, selection means coupled to said radio frequency mixers for selecting one of the mixer output signals other than that one output identifying the particular phase of the incoming signal, and amplifier means coupled to said selection means and to said tunable radio frequency source for producing an error signal dependent on said selected one of the mixer output signals to tune said radio frequency source to the frequency of said incoming signal.
Claim 2
Dependent Claim
349 words
Apparatus for the recovery of synchronous carrier for coherent detection of a signal in a digital communication system, the incoming signal consisting of a series of successive time intervals of radio frequency signal, the phase of the radio frequency signal during each time interval being any one of a plurality of different phases, said apparatus comprising, means for splitting the incoming signal into two parts, a tunable radio frequency source of substantially the same frequency as said incoming signal, a first radio frequency mixer mixing one of said incoming signal parts with a reference radio frequency signal from said tunable radio frequency source to obtain a pair of output signals with sign dependent on the direction of the phase shift between the incoming signal and the reference signal and with amplitude dependent on the degree of phase shift between the incoming and reference signals, said two output signals having opposite signs, phase shifting means coupled to said radio frequency source for providing a second reference radio frequency signal in quadrature with said first reference signal, a second radio frequency mixer for mixing the second one of said incoming signal parts with said second reference signal to obtain a second pair of output signals with sign dependent on the direction of the phase shift between the incoming signal and the second reference signal and with amplitude dependent on the degree of phase shift between the incoming and second reference signals, said two second output signals having opposite signs, means coupled to said radio frequency mixers and responsive to differnet ones of said four mixer output signals operative to identify the possible phases of the incoming radio frequency signal, selection means coupled to said radio frequency mixers for selecting one of the mixer output signals other than that one output identifying the particular phase of the incoming signal, and amplifier means coupled to said selection means and to said tunable radio frequency source for producing an error signal dependent on said selected one of the mixer output signals to tune said radio frequency source to the frequency of said incoming signal.
Claim 3
Dependent Claim
12 words
Apparatus as claimed in claim 1 wherein said incoming signal is biphase.
Claim 4
Dependent Claim
12 words
Apparatus as claimed in claim 1 wherein said incoming signal is quadraphase.
Claim 5
Dependent Claim
94 words
Apparatus as claimed in claim 1 wherein said amplifier means comprises an output transistor having an input and an output, and said selection means comprises a plurality of separate input circuits each coupled to the input of said output transistor, each input circuit comprising means for activating the associated input circuit responsive to an associated one of the plurality of mixer output signals, and means in said activated input circuit responsive to a different one of said plurality of mixer output signals than said activating one for controlling the input of said transistor circuit.
Claim 6
Dependent Claim
61 words
Apparatus as claimed in claim 4 Wherein each of said input circuits includes a first transistor in series with a second transistor, said first transistor being activated by said one mixer output signal and providing current to said second transistor, said second transistor responding to said different one of the mixer output signals for controlling the input to said output transistor.
Claim 7
Independent Claim
291 words
A method for the recovery of synchronous carrier for coherent detection of a signal in a digital communication system, the incoming signal consisting of a series of successive time intervals of radio frequency signal, the phase of the radio frequency signal during each time interval being any one of a plurality of different phases, said method comprising the steps of splitting the incoming signal into two parts, mixing one of said incoming signal parts with a reference radio frequency signal of substantially the same frequency from a tunable radio frequency source to obtain a pair of output signals with sign dependent on the direction of the phase shift between the incoming signal and the reference signal and with amplitude dependent on the degree of phase shift between the incoming and reference signals, said two output signals having opposite signs, mixing the second one of said incoming signal parts with a second reference signal from said tunable radio frequency source in phase quadrature with said first radio frequency signal to obtain a second pair of output signals with sign dependent on the direction of the phase shift between the incoming signal and the second reference signal and with amplitude dependent on the degree of phase shift between the incoming and second reference signals, said two second output signals having opposite signs, different ones of said four mixer output signals serving to identify different ones of the possible phases of the incoming radio frequency signal, selecting one of the mixer output signals other than that one output identifying the particular phase of the incoming signal, and producing an error signal dependent on said selected one of the mixer output signals to tune said radio frequency source to the frequency of said incoming signal,
Claim 8
Independent Claim
291 words
A method for the recovery of synchronous carrier for coherent detection of a signal in a digital communication system, the incoming signal consisting of a series of successive time intervals of radio frequency signal, the phase of the radio frequency signal during each time interval being any one of a plurality of different phases, said method comprising the steps of splitting the incoming signal into two parts, mixing one of said incoming signal parts with a reference radio frequency signal of substantially the same frequency from a tunable radio frequency source to obtain a pair of output signals with sign dependent on the direction of the phase shift between the incoming signal and the reference signal and with amplitude dependent on the degree of phase shift between the incoming and reference signals, said two output signals having opposite signs, mixing the second one of said incoming signal parts with a second reference signal from said tunable radio frequency source in phase quadrature with said first radio frequency signal to obtain a second pair of output signals with sign dependent on the direction of the phase shift between the incoming signal and the second reference signal and with amplitude dependent on the degree of phase shift between the incoming and second reference signals, said two second output signals having opposite signs, different ones of said four mixer output signals serving to identify different ones of the possible phases of the incoming radio frequency signal, selecting one of the mixer output signals other than that one output identifying the particular phase of the incoming signal, and producing an error signal dependent on said selected one of the mixer output signals to tune said radio frequency source to the frequency of said incoming signal,
Claim 9
Dependent Claim
13 words
The method as claimed in claim 6 wherein said incoming signal is biphase.
Claim 10
Dependent Claim
13 words
The method as claimed in claim 6 wherein said incoming signal is quadraphase.
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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |