Patent US3581235A successfully refreshed from Google Patents.
US3581235A
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Crystal stabilized high frequency transistor multivibrator
Assignee: Unisys Corp
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Filing: 1969-02-19
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Granted: 1971-05-25
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Expires: 1989-02-19
Abstract
Abstract An astable multivibrator operating in a current mode comprising two transistors with resistive cross-coupling between each collector and the other base and capacitive cross-coupling between emitters. The natural frequency of the multivibrator is determined by the emitter resistors and the cross-coupling capacitance, which is preferably adjustable. A crystal having a parallel resonant overtone mode at the desired frequency of operation of the oscillator is connected between the bases of the transistors. The cross-coupling capacitance is adjusted so that the natural frequency of the multivibrator is slightly higher than the resonant frequency of the crystal.
Inventors
- 👤 Paul Y Siu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:37
CPC Classifications
H; H03; H03K; H03K4/00; H03K4/06; H03K3/00; H03K3/02; H03K3/26; H03K3/28; H03K3/281; H03K3/282; H03K3/283
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
15 words
The oscillator of claim 1, in which the capacitance of the capacitive cross-coupling is adjustable.
Claim 2
Dependent Claim
17 words
The oscillator of claim 1, in which the resonant frequency of the crystal is an overtone mode.
Claim 3
Dependent Claim
15 words
The oscillator of claim 3, in which the capacitance of the capacitive cross-coupling is adjustable.
Claim 4
Dependent Claim
28 words
The oscillator of claim 4, in which the bias providing means are adapted so the voltage across the capacitive cross-coupling increases linearly during each half cycle of operation.
Claim 5
Dependent Claim
28 words
The oscillator of claim 1, in which the bias providing means are adapted so the voltage across the capacitive cross-coupling increases linearly during each half cycle of operation.
Claim 6
Dependent Claim
103 words
A stable oscillator comprising: an astable multivibrator having first and second active elements each with a control terminal, the active elements alternately conducting and cutting off at a natural frequency, a capacitive coupling between the active elements, the voltage across the capacitive coupling determining which active element is conducting and which active element is cut off, and means for charging and discharging the capacitive coupling such that the voltage thereacross changes linearly; and a crystal connected between the control terminals of the active elements, the crystal having a parallel resonant mode at a frequency slightly less than the natural frequency of the multivibrator.
Claim 7
Dependent Claim
17 words
The oscillator of claim 7, in which the parallel resonant mode of the crystal is an overtone.
Claim 8
Dependent Claim
20 words
The oscillator of claim 1, in which the applying means operates the first and second transistors in the current mode.
Claim 9
Dependent Claim
19 words
The oscillator of claim 1, in which the applying means applies a constant charging current to the capacitive cross-coupling
References Cited (Backward Citations)
DE545901C
Cited
US3217269A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |