US3569838A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wide range frequency synthesizer
Assignee: GTE Sylvania Inc
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Filing: 1968-04-03
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Granted: 1971-03-09
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Expires: 1988-04-03
Abstract
Abstract A frequency synthesizer particularly suitable for VHF applications comprising a pair of variable frequency oscillators adapted to be simultaneously tuned in coarse frequency steps, one of the oscillators being phase locked to a frequency standard, and the second oscillator being controlled by a tunable frequency lock loop referenced to the first oscillator to provide the synthesized frequency output. The tunable frequency lock loop includes a balanced mixer coupled at the outputs of the two oscillators for producing a difference frequency, a frequency discriminator for providing a voltage signal proportional to this difference frequency, a continuously or discretely variable tuning voltage, and a difference amplifier which compares the discriminator output with a selected tuning voltage and provides a difference signal for fine tuning the second oscillator.
Inventors
- 👤 David J Blair
- 👤 George H Kam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:04
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/22
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
170 words
A frequency synthesizer comprising, in combination, a first oscillator having an output and adapted to be controlled in frequency By input signals applied thereto, a first mixer having first and second inputs and an output, the output of said first oscillator being coupled to the first input of said first mixer, a reference frequency source coupled to the second input of said first mixer, said reference frequency source being adapted to be controlled in frequency, means for simultaneously tuning said first oscillator and said reference frequency source in coarse frequency steps, a difference amplifier having first and second inputs and an output, a frequency discriminator coupled between the output of said first mixer and the first input of said difference amplifier, a variable tuning voltage source connected to the second input of said difference amplifier, and means connecting the output of said difference amplifier to an input of said first oscillator whereby the frequency of said first oscillator is controlled in response to the difference signal generated from said amplifier.
Claim 2
Dependent Claim
170 words
A frequency synthesizer comprising, in combination, a first oscillator having an output and adapted to be controlled in frequency By input signals applied thereto, a first mixer having first and second inputs and an output, the output of said first oscillator being coupled to the first input of said first mixer, a reference frequency source coupled to the second input of said first mixer, said reference frequency source being adapted to be controlled in frequency, means for simultaneously tuning said first oscillator and said reference frequency source in coarse frequency steps, a difference amplifier having first and second inputs and an output, a frequency discriminator coupled between the output of said first mixer and the first input of said difference amplifier, a variable tuning voltage source connected to the second input of said difference amplifier, and means connecting the output of said difference amplifier to an input of said first oscillator whereby the frequency of said first oscillator is controlled in response to the difference signal generated from said amplifier.
Claim 3
Dependent Claim
84 words
A frequency synthesizer according to claim 1 wherein said first mixer is operative to produce an output which is the difference frequency of the first oscillator and reference frequency inputs thereto, and wherein the variable tuning voltage source connected to the second input of said difference amplifier is calibrated to enable variation of said first oscillator frequency within a selected range, one end point of which establishes a minimum difference frequency sufficient to prevent said first oscillator from locking onto said reference frequency source.
Claim 4
Dependent Claim
48 words
A frequency synthesizer according to claim 2 wherein said frequency discriminator comprises a monostable multivibrator, the trigger input of which is coupled to the output of said first mixer, and an integrator circuit connected between the output of said monostable and the first input of said difference amplifier.
Claim 5
Dependent Claim
201 words
A frequency synthesizer according to claim 1 wherein said reference frequency source comprises, a second oscillator having an input and adapted to be controlled in frequency and phase by input signals applied thereto, a second mixer having first and second inputs and an output, the output of said second oscillator being coupled in parallel to the second input of said first mixer and the first input of said second mixer, a frequency standard, a harmonic generator driven by said frequency standard, means coupling the output of said harmonic generator to the second input of said second mixer, a phase detector having first and second inputs and an output, a first filter coupled between the output of said harmonic generator and the first input of said phase detector for passing a selected harmonic of said frequency standard, a second filter coupled between the output of said second mixer and the second input of said phase detector for passing the same frequency selected by said first filter, and means connecting the output of said phase detector to an input of said second oscillator whereby the phase of said second oscillator is corrected in response to the error signal generated from said phase detector.
Claim 6
Dependent Claim
22 words
A frequency synthesizer according to claim 4 further including means for simultaneously tuning said first and second oscillators in coarse frequency steps.
Claim 7
Dependent Claim
48 words
A frequency synthesizer according to claim 5 wherein said frequency discriminator comprises a monostable multivibrator, the trigger input of which is coupled to the output of said first mixer, and an integrator circuit connected between the output of said monostable and the first input of said difference amplifier.
Claim 8
Dependent Claim
87 words
A frequency synthesizer according to claim 6 wherein said first mixer is operative to produce an output which is the difference frequency of the first and second oscillator inputs thereto, and wherein the variable tuning voltage source connected to the second input of said difference amplifier comprises a variable resistor voltage divider calibrated to enable variation of said first oscillator frequency within a selected range, one end point of which establisheS a minimum difference frequency sufficient to prevent said first oscillator from locking onto said second 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) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |