US3587003A
Expired / Lapsed
US
⏱️ 0.0 years remaining
An automatic frequency control system for a frequency modulation circuit having an asymmetric input signal
Assignee: US Philips Corp
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Filing: 1969-09-30
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Granted: 1971-06-22
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Expires: 1989-09-30
Abstract
Abstract An automatic frequency control system for a frequency modulation circuit comprising a voltage-controlled, frequency-modulated oscillator having an asymmetric input signal and a reference oscillator coupled to a comparison detection circuit, which feeds back a control voltage compensated by the mean value of the asymmetry of the signal input to the voltage-controlled oscillator so that the circuit''s output frequency is always at a harmonic of the frequency of the reference oscillator.
Inventors
- 👤 Jean Chastagnier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:15
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/02; H03C3/09; H03C3/0908; H03C3/0975; H03C3/0941; H03C3/0958; H03C3/0966; H03C2200/00; H03C2200/0037; H03C2200/0075
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
119 words
An automatic frequency control system for a frequency modulation circuit, comprising input means for receiving asymmetric signals, a voltage-controlled oscillator for producing frequency-modulated output signals having frequency variations as determined by said input signals, a reference oscillator for producing signals at a constant frequency, comparison detection circuit means having separate input paths from each of said input means, said voltage-controlled oscillator and said reference oscillator to produce control voltages having values as determined by frequency differences between said voltagecontrolled oscillator and said reference oscillator and by asymmetries of said input signal, and means for applying said control voltages to said voltage-controlled oscillator thereby to produce frequency-modulated output signals having a mean frequency value determined by said reference oscillator frequency.
Claim 2
Dependent Claim
119 words
An automatic frequency control system for a frequency modulation circuit, comprising input means for receiving asymmetric signals, a voltage-controlled oscillator for producing frequency-modulated output signals having frequency variations as determined by said input signals, a reference oscillator for producing signals at a constant frequency, comparison detection circuit means having separate input paths from each of said input means, said voltage-controlled oscillator and said reference oscillator to produce control voltages having values as determined by frequency differences between said voltagecontrolled oscillator and said reference oscillator and by asymmetries of said input signal, and means for applying said control voltages to said voltage-controlled oscillator thereby to produce frequency-modulated output signals having a mean frequency value determined by said reference oscillator frequency.
Claim 3
Dependent Claim
32 words
An automatic frequeNcy control system as claimed in claim wherein said comparison detection circuit means comprises voltage-controlled oscillator and reference oscillator frequency dividing means proportional to the frequency of said reference oscillator.
Claim 4
Dependent Claim
75 words
An automatic frequency control system as claimed in claim 1 wherein said comparison detection circuit means comprises means for comparing frequencies of said voltage-controlled oscillator and said reference oscillator to produce voltages having values representing the frequency differences thereof, detecting means for producing voltages having values representing the mean value of asymmetry of said input signals, and means for combining the voltages of said comparing means and said detecting means to produce said control voltages.
Claim 5
Dependent Claim
81 words
An automatic frequency control system as claimed in claim 1 wherein said comparison detection circuit means comprises detecting means for producing voltages representing the mean value of asymmetry of said input signals, phase modulator means for modifying the frequency of said reference oscillator by said detected voltages to provide for the asymmetry of said input signals, and phase discriminator means for comparing the frequency of said voltage-controlled oscillator with output signals of said phase modulator means to produce said control voltage.
Claim 6
Dependent Claim
135 words
An automatic frequency control system for a frequency modulation circuit comprising input means for receiving asymmetric signals, a reference oscillator for producing signals at a predetermined constant frequency, means for dividing the frequency of said reference oscillator, phase modulator means for modifying the divided frequency of said reference oscillator by said input signal to provide for the asymmetry of said input signal, voltage-controlled oscillator for producing frequency-modulated signals, means for dividing the frequency-modulated signals of said oscillator by a constant determined by the divided frequency of said reference oscillator, phase-discriminating means connected to said phase-modulating means and said voltage-controlled oscillator-dividing means to produce a value of voltage determined by the frequency differences thereof, and means for supplying said control voltage to said voltage-controlled oscillator thereby to produce frequency-modulated signals determined by said reference oscillator frequency.
Claim 7
Dependent Claim
135 words
An automatic frequency control system for a frequency modulation circuit comprising input means for receiving asymmetric signals, a reference oscillator for producing signals at a predetermined constant frequency, means for dividing the frequency of said reference oscillator, phase modulator means for modifying the divided frequency of said reference oscillator by said input signal to provide for the asymmetry of said input signal, voltage-controlled oscillator for producing frequency-modulated signals, means for dividing the frequency-modulated signals of said oscillator by a constant determined by the divided frequency of said reference oscillator, phase-discriminating means connected to said phase-modulating means and said voltage-controlled oscillator-dividing means to produce a value of voltage determined by the frequency differences thereof, and means for supplying said control voltage to said voltage-controlled oscillator thereby to produce frequency-modulated signals determined by said reference oscillator frequency.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |