Patent US3916335A successfully refreshed from Google Patents.
US3916335A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Harmonically phase locked voltage controlled oscillator
Assignee: Raytheon Co
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Filing: 1974-09-06
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Granted: 1975-10-28
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Expires: 1994-09-06
Abstract
Abstract A highly stable microwave source in which a voltage controlled oscillator (VCO) is harmonically phase locked to a crystal reference source and in which the desired harmonic of the reference source is accurately and reliably selected by sweeping the VCO until it is reached. The reference source, phase comparator, a loop amplifier and VCO are arranged to form the harmonic phase locked loop. A one shot circuit initiates a sweep voltage to sweep the VCO from its initial frequency to either a higher or lower frequency. A marker cavity is provided which responds to the output of the VCO so that when the signal crosses the frequency of the cavity, a flip-flop is set to enable a zero beat detector to provide pulses to increment a counter as each harmonic is crossed. When the count equals a selected digital code, the loop is phase locked to the correct harmonic and a comparator is energized to disconnect the sweep voltage from the VCO. The system operates in one arrangement in accordance with the invention to continue selecting a harmonic until two sweep cycles provide the same VCO control voltage, resulting in a highly reliable selection of the desired harmonic. The selection system in accordance with the invention permits the VCO to have an output bandwidth that is limited only by the VCO tuning range and allows selection of a large number of different harmonics of different reference sources.
Inventors
- 👤 Ronald K Masson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:24
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/10; H03L7/12; H03L7/16; H03L7/20
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
133 words
A system for providing a stable frequency from a voltage controlled oscillator having a control input, an output and a phase comparator coupled between said output and said control input comprising: counter means; zero beat detector means coupled from the output of said phase comparator to said counter means; cavity means coupled from the output of said voltage controlled oscillator to said counter means for starting said counter means to count the zero beat detections; sweep generator means coupled to the input of said voltage controlled oscillator; and control means coupled to said sweep generator means and to said counter means for starting the sweep generator to apply a sweep signal to said voltage controlled oscillator and for terminating the sweep signal in response to a predetermined count provided by said counter means.
Claim 2
Independent Claim
133 words
A system for providing a stable frequency from a voltage controlled oscillator having a control input, an output and a phase comparator coupled between said output and said control input comprising: counter means; zero beat detector means coupled from the output of said phase comparator to said counter means; cavity means coupled from the output of said voltage controlled oscillator to said counter means for starting said counter means to count the zero beat detections; sweep generator means coupled to the input of said voltage controlled oscillator; and control means coupled to said sweep generator means and to said counter means for starting the sweep generator to apply a sweep signal to said voltage controlled oscillator and for terminating the sweep signal in response to a predetermined count provided by said counter means.
Claim 3
Dependent Claim
29 words
The combination of claim 1 in which said control means includes the comparator for comparing the count with an input code and upon an equality terminating the sweep signal.
Claim 4
Dependent Claim
42 words
The combination of claim 2 in which detecting means is coupled between said cavity means and said counter means for providing a pulse when the output frequency of said voltage controlled oscillator is equal to the cavity frequency to start the counter.
Claim 5
Dependent Claim
75 words
The combination of claim 3 in which said control means includes capacitor means coupled to the control input of said voltage controlled oscillator at the termination of each sweep to provide a reset pulse when the voltage at the control input is different than at the end of the previous sweep, said capacitor means being coupled to said control means to apply said reset pulse to initiate an additional sweep of said voltage controlled oscillator.
Claim 6
Independent Claim
207 words
A system for providing a signal of a selected frequency comprising: a voltage controlled oscillator having a control terminal and an output terminal; a phase locked loop coupled between the output terminal and the control terminal of said voltage controlled oscillator and including a phase detector; reference means coupled to said phase detector; a sweep generator coupled to the control input of said oscillator; a zero beat detector having an input and an output with said input coupled to said phase comparator; a counter having an input gate coupled to the output of said zero beat detector; A cavity coupled to the output of said voltage controlled oscillator; a counter flip-flop coupled from said cavity to the input gate of said counter for being set in response to said cavity receiving a predetermined frequency at the output of said voltage controlled oscillator; a source of a count code; a digital comparator coupled to said counter and the code source and to said sweep generator for terminating the generations of a sweep voltage upon a predetermined comparison of the count from said counter and said count code; a control flip-flop; and first control means coupled to said control flip-flop and said sweep generator for initiating a sweep voltage.
Claim 7
Independent Claim
207 words
A system for providing a signal of a selected frequency comprising: a voltage controlled oscillator having a control terminal and an output terminal; a phase locked loop coupled between the output terminal and the control terminal of said voltage controlled oscillator and including a phase detector; reference means coupled to said phase detector; a sweep generator coupled to the control input of said oscillator; a zero beat detector having an input and an output with said input coupled to said phase comparator; a counter having an input gate coupled to the output of said zero beat detector; A cavity coupled to the output of said voltage controlled oscillator; a counter flip-flop coupled from said cavity to the input gate of said counter for being set in response to said cavity receiving a predetermined frequency at the output of said voltage controlled oscillator; a source of a count code; a digital comparator coupled to said counter and the code source and to said sweep generator for terminating the generations of a sweep voltage upon a predetermined comparison of the count from said counter and said count code; a control flip-flop; and first control means coupled to said control flip-flop and said sweep generator for initiating a sweep voltage.
Claim 8
Dependent Claim
36 words
The combination of claim 5 further including capacitive means coupled to the control terminal of said voltage controlled oscillator and to said control flip-flop for resetting said flip-flop and causing said sweep generator to be actuated.
Claim 9
Dependent Claim
70 words
The combination of claim 6 in which said capacitive means includes a capacitor and a gate with said gate coupled between the control terminal of said voltage controlled oscillator and said capacitor and being responsive to said first control means to open upon the occurrence of a sweep and to close upon termination of a sweep, said capacitor charging to initiate a second sweep after termination of a first sweep.
Claim 10
Dependent Claim
40 words
The combination of claim 7 in which an ambiguity selection circuit is coupled between said cavity and said counter flip-flop for selectively setting said counter flip-flop on either the leading or trailing edge of a pulse derived from said cavity.
Claim 11
Independent Claim
126 words
A system for controlling a voltage controlled oscillator having a control terminal and an output lead coupled to a phase locked loop to lock on a selected harmonic of a reference source comprising: sweep generator means coupled to the control terminal of said oscillator; cavity means coupled to the output lead of said voltage controlled oscillator for providing a pulse at a predetermined frequency; counter means coupled to said phase locked loop and to said cavity means for counting the harmonics after occurrence of a pulse from said cavity means; first control means coupled to said sweep generator means for starting a sweep; and second control means coupled to said sweep generator means and responsive to said counter for terminating said sweep at a predetermined count.
Claim 12
Independent Claim
126 words
A system for controlling a voltage controlled oscillator having a control terminal and an output lead coupled to a phase locked loop to lock on a selected harmonic of a reference source comprising: sweep generator means coupled to the control terminal of said oscillator; cavity means coupled to the output lead of said voltage controlled oscillator for providing a pulse at a predetermined frequency; counter means coupled to said phase locked loop and to said cavity means for counting the harmonics after occurrence of a pulse from said cavity means; first control means coupled to said sweep generator means for starting a sweep; and second control means coupled to said sweep generator means and responsive to said counter for terminating said sweep at a predetermined count.
Claim 13
Dependent Claim
49 words
The combination of claim 9 in which said first control means includes capacitive means for holding a charge representative of the control potential at the beginning of a first sweep and initiating a second sweep if the potential varies a predetermined amount at the end of said first sweep.
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |