US3919651A
Expired / Lapsed
US
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Phase differential modulation frequency automatic correcting device
Assignee: LANNIONNAIS ELECTRONIQUE
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Filing: 1974-04-19
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Granted: 1975-11-11
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Expires: 1994-04-19
Abstract
Abstract Correcting device ensuring automatically, at the receiving end, an exact timing of the frequency demodulated at the rated value, that timing being necessary for the demodulation to be effected properly, the correction being effected by a frequency servocontrolling based on an error signal extracted from a frequency discriminator in determined conditions.
Inventors
- 👤 Mouel Bernard Le
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:26
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
118 words
An automatic frequency corrector for a local oscillator used for a frequency transposition for a demodulator of a differential phase modulated wave comprising a phase discriminator receiving on a first input said modulated wave and on a second input the same modulated wave delayed by an instant Tau , a sampling unit having one input connected to tHe output of said phase discriminator, a pulse generator connected to a second input of said sampling unit, and control means responsive to said modulated wave for triggering said pulse generator at the instants when the output of said phase discriminator is zero at a selected frequency and when the output of said phase discriminator is non-zero at all other frequencies.
Claim 2
Dependent Claim
118 words
An automatic frequency corrector for a local oscillator used for a frequency transposition for a demodulator of a differential phase modulated wave comprising a phase discriminator receiving on a first input said modulated wave and on a second input the same modulated wave delayed by an instant Tau , a sampling unit having one input connected to tHe output of said phase discriminator, a pulse generator connected to a second input of said sampling unit, and control means responsive to said modulated wave for triggering said pulse generator at the instants when the output of said phase discriminator is zero at a selected frequency and when the output of said phase discriminator is non-zero at all other frequencies.
Claim 3
Dependent Claim
46 words
An automatic frequency corrector as defined in claim 1 further including means for dividing said modulated wave into first and second identical signals, a delay unit receiving said first signal and connected to said phase discriminator, and means applying said second signal to said control means.
Claim 4
Dependent Claim
37 words
An automatic frequency corrector as defined in claim 2 wherein said control means includes a demodulator receiving said second signal and a decoder connected between the output of said demodulator and the input of said pulse generator.
Claim 5
Dependent Claim
21 words
An automatic frequency corrector as defined in claim 3 wherein the instant Tau corresponds to a quadrature of the modulated wave.
Claim 6
Dependent Claim
61 words
An automatic frequency corrector as defined in claim 3 wherein said control means includes a shift register connected to the output of said decoder and logic means connected between said shift register and said pulse generator for triggering said pulse generator only in response to a predetermined number of successive logic states corresponding to a zero dephasing of said modulated wave.
Claim 7
Dependent Claim
53 words
An automatic frequency corrector as defined in claim 1, wherein said oscillator transposes said modulated wave into an intermediate frequency wave, said intermediate frequency wave being applied to the inputs of said phase discriminator, and wherein means responsive to said sampling unit is included for applying an error correction signal to said oscillator.
Claim 8
Dependent Claim
17 words
An automatic frequency corrector as defined in claim 6, wherein said oscillator includes a variable frequency oscillator.
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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |