US4119925A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency synthesizer with frequency modulated output
Assignee: RCA Corp
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Filing: 1977-05-16
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Granted: 1978-10-10
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Expires: 1997-05-16
Abstract
Abstract A frequency synthesizer having a frequency-locked loop providing any digitally selected output frequency, and means to frequency modulate the selected output frequency at an audio rate. The frequency-locked loop includes a frequency-to-current converter coupled to the output of a voltage-controlled oscillator to provide a current, representing the actual frequency of the oscillator, which is compared with a current representing a desired output frequency. A resulting error signal controls the oscillator center frequency, which can be frequency modulated by an audio-frequency signal.
Inventors
- 👤 Robert Jan Bosselaers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:49
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/02; H03C3/09; H03C3/0908; H03C3/095
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
162 words
Means to generate an output signal having a desired center frequency, and to frequency modulate said output signal, comprising a voltage-controlled oscillator providing said output signal, a frequency divider coupled to the output of said oscillator, a frequency-to-current converter connected to the output of said frequency divider and producing an actual-frequency-representing current corresponding with the frequency of said output signal, a digital-to-analog converter converting an input digital signal representing a desired output signal frequency to a corresponding desired-frequency-representing current, means to produce an error current representing the difference between said actual-frequency-representing current and said desired-frequency-representing current, a current-controlled voltage source translating said error current to a corresponding error voltage, a low-pass filter, and an integrator, coupling said error voltage to the control voltage input of said voltage-controlled oscillator, to produce an output at the desired center frequency, and means to apply an audio-frequency modulating voltage also to the input of said integrator, to frequency modulate the output signal from said voltage-controlled oscillator.
Claim 2
Dependent Claim
162 words
Means to generate an output signal having a desired center frequency, and to frequency modulate said output signal, comprising a voltage-controlled oscillator providing said output signal, a frequency divider coupled to the output of said oscillator, a frequency-to-current converter connected to the output of said frequency divider and producing an actual-frequency-representing current corresponding with the frequency of said output signal, a digital-to-analog converter converting an input digital signal representing a desired output signal frequency to a corresponding desired-frequency-representing current, means to produce an error current representing the difference between said actual-frequency-representing current and said desired-frequency-representing current, a current-controlled voltage source translating said error current to a corresponding error voltage, a low-pass filter, and an integrator, coupling said error voltage to the control voltage input of said voltage-controlled oscillator, to produce an output at the desired center frequency, and means to apply an audio-frequency modulating voltage also to the input of said integrator, to frequency modulate the output signal from said voltage-controlled oscillator.
References Cited (Backward Citations)
US3735276A
Cited
US4052672A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-09 | 1982-04-10 | 1982-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-09 | 1986-04-10 | 1986-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-09 | 1990-04-10 | 1990-10-10 | $7700.00 | Window Closed / Lapsed |