Patent US3569865A successfully refreshed from Google Patents.
US3569865A
Expired / Lapsed
US
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High stability voltage-controlled crystal oscillator
Assignee: United States Department of the Navy
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Filing: 1969-06-12
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Granted: 1971-03-09
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Expires: 1989-06-12
Abstract
Abstract A high stability voltage-controlled crystal oscillator having a series coupled emitter follower transistor amplifier with a regenerative feedback to a tuned circuit coupled to the base electrode of the amplifier, the tuned circuit having a narrow band-pass crystal filter in series with a variable capacity device and in parallel with a low Q inductance with a control voltage adapted to be coupled to the variable capacity device to vary the capacitive reactance of the tuned circuit to produce oscillations over a limited frequency range with high stability.
Inventors
- 👤 Daniel J Healey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:42
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/10; H03C3/12; H03C3/22; H03C3/222
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
185 words
A high stability voltage-controlled crystal oscillator comprising: an amplifier having an input and an output; a tuned circuit coupled to said amplifier input with a crystal unit and a pair of variable capacitance diodes in anode backto-back relation in series with said input with the cathode of one coupled to said crystal unit, the cathode of the other coupled through a first high resistance to a fixed potential, and a control voltage coupled to said common back-to-back coupling of said pair of variable capacitance diodes through a second high resistance to vary the capacitive reactance of said pair of variable capacitance diodes, and a low Q first inductance in parallel with said crystal unit; and a feedback circuit from the output of said amplifier to said tuned circuit to regeneratively sustain oscillations on the output of said amplifier produced by the time constant established in said tuned circuit whereby said crystal unit and parallel inductance thereto establish an anharmonic resistance and reactance relationship to produce a stable output frequency variable within limits produced by varying the capacitive reactance of said pair of variable capacitance diodes.
Claim 2
Dependent Claim
185 words
A high stability voltage-controlled crystal oscillator comprising: an amplifier having an input and an output; a tuned circuit coupled to said amplifier input with a crystal unit and a pair of variable capacitance diodes in anode backto-back relation in series with said input with the cathode of one coupled to said crystal unit, the cathode of the other coupled through a first high resistance to a fixed potential, and a control voltage coupled to said common back-to-back coupling of said pair of variable capacitance diodes through a second high resistance to vary the capacitive reactance of said pair of variable capacitance diodes, and a low Q first inductance in parallel with said crystal unit; and a feedback circuit from the output of said amplifier to said tuned circuit to regeneratively sustain oscillations on the output of said amplifier produced by the time constant established in said tuned circuit whereby said crystal unit and parallel inductance thereto establish an anharmonic resistance and reactance relationship to produce a stable output frequency variable within limits produced by varying the capacitive reactance of said pair of variable capacitance diodes.
Claim 3
Dependent Claim
76 words
A high stability voltage-controlled crystal oscillator as set forth in claim 1 wherein said tuned circuit includes a second inductance, first, second, and third capacitors in series, this series being in parallel to the series coupling of said crystal and variable capacity diodes, said feedback from the output of said amplifier being coupled to the junction of said first and second capacitors and a fixed potential coupled to the junction of said second and third capacitors.
Claim 4
Dependent Claim
51 words
A high stability voltage-controlled crystal oscillator as set forth in claim 2 wherein said amplifier consists of a pair of emitter-to-base coupled transistors, said tuned circuit being coupled to the base of the first transistor and said output being coupled through an output resistor from the emitter of the second transistor.
Claim 5
Dependent Claim
36 words
A high stability voltage controlled crystal oscillator as set forth in claim 3 wherein said tuned circuit includes a third high resistance in parallel with said pair of variable capacitance diodes and said first large resistance.
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 |