US3875533A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Crystal controlled overtone oscillator having a rejection circuit for preventing oscillation at undesired overtones
Assignee: Motorola Solutions Inc
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Filing: 1973-10-15
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Granted: 1975-04-01
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Expires: 1993-10-15
Abstract
Abstract A crystal controlled overtone oscillator having a feedback circuit comprising a series connected inductance-capacitance arm having the values of the inductance and capacitance chosen to provide a net inductive reactance at the desired overtone and a net capacitive reactance at lower overtones, and a shunt inductance-capacitance arm that is resonant at the desired overtone. A broadband neutralization network is employed to neutralize the static shunt capacitance of the crystal and to provide the shunt inductance-capacitance arm.
Inventors
- 👤 James S Irwin
- 👤 Francis R Steel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:33
CPC Classifications
H; H03; H03B; H03B5/00; H03B5/30; H03B5/32; H03B5/36; H03B5/362; H03B2200/00; H03B2200/0002; H03B2200/0008
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
180 words
A crystal controlled overtone oscillator comprising: an amplifier having first, second and third terminals; a point of reference potential connected to said third terminal; a piezoelectric crystal having a predetermined overtone operating frequency and other resonant frequencies; an inductor and a capacitor conncted in a series circuit with said crystal, said series circuit being connected in series between the first and second terminals of said amplifier, said inductor and capacitor having values chosen such that the inductive reactance of said inductor is greater than the capacitive reactance of said inductor is greater than the capacitive reactance of said capacitor at said predetermined overtone operating frequency, said inductor and capacitor further arranged to form the inductive tuning element of a Colpitts oscillator, and the inductive reactance of said inductor is less than the capacitive reactance of said capacitor at resonant frequencies of said crystal lower than said predetermined overtone operating frequency; and parallel connected inductance-capacitance means connected betweeen a terminal of said crystal and the point of reference potential, said inductance-capacitance means being parallel resonant at said predetermined overtone operating frequency.
Claim 2
Dependent Claim
180 words
A crystal controlled overtone oscillator comprising: an amplifier having first, second and third terminals; a point of reference potential connected to said third terminal; a piezoelectric crystal having a predetermined overtone operating frequency and other resonant frequencies; an inductor and a capacitor conncted in a series circuit with said crystal, said series circuit being connected in series between the first and second terminals of said amplifier, said inductor and capacitor having values chosen such that the inductive reactance of said inductor is greater than the capacitive reactance of said inductor is greater than the capacitive reactance of said capacitor at said predetermined overtone operating frequency, said inductor and capacitor further arranged to form the inductive tuning element of a Colpitts oscillator, and the inductive reactance of said inductor is less than the capacitive reactance of said capacitor at resonant frequencies of said crystal lower than said predetermined overtone operating frequency; and parallel connected inductance-capacitance means connected betweeen a terminal of said crystal and the point of reference potential, said inductance-capacitance means being parallel resonant at said predetermined overtone operating frequency.
Claim 3
Dependent Claim
29 words
A crystal controlled overtone oscillator as recited in claim 1, wherein said amplifier circuit further includes capacitor means connected between the second and third terminals of said amplifier circuits.
Claim 4
Dependent Claim
27 words
An oscillator circuit as recited in claim 2 wherein said amplifier circuit includes means for providing a 180* phase shift between the first and second terminals thereof.
Claim 5
Dependent Claim
102 words
An oscillator circuit as recited in claim 3 wherein said crystals has a predetermined static shunt capacitance in parallel therewith, and wherein said oscillator circuit includes a neutralizing circuit having first, second and third terminals; means connecting said first terminal to a first terminal of said crystal, further means connecting said second terminal to a second terminal of said crystal, means connecting said third terminal to said point of reference potential and a predetermined inductive reactance substantially equal to one half the capacitive reactance of said static shunt capacitance between the first and third terminals thereof at said predetermined overtone operating frequency.
Claim 6
Dependent Claim
57 words
An oscillator circuit as recited in claim 4 wherein said neutralizing circuit includes transformer means having primary and secondary winding means, the self inductance of said primary winding means being selected such that the inductive reactance thereof at said predetermined overtone operating frequency is substantially equal to one half the capacitive reactance of said static shunt capacitance.
Claim 7
Dependent Claim
56 words
An oscillator circuit as recited in claim 4 wherein the difference between the inductive reactance of said inductor and the capacitive reactance of said capacitor at said predetermined overtone operating frequency is approximately equal to the sum of the capacitive reactance of said capacitor means plus one half the capacitive reactance of said static shunt capacitance.
Claim 8
Dependent Claim
24 words
An oscillator circuit as recited in claim 6 further including second capacitor means connected between the first and third terminals of said amplifier circuit.
Claim 9
Dependent Claim
34 words
An oscillator circuit as recited in claim 7 wherein said amplifier circuit includes a transistor having base, collector and emitter electrodes coupled to said first, second and third terminals, respectively, of said amplifier circuit.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |