US5004987A
Expired / Lapsed
US
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Temperature compensated crystal resonator found in a dual-mode oscillator
Assignee: Piezo Crystal Co
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Filing: 1989-05-19
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Granted: 1991-04-02
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Expires: 2009-05-19
Abstract
Abstract A device utilizing a quartz crystal resonator with an orientation substantially equal to 21.93°/34.10°. The crystal resonator is capable of vibrating simultaneously in two thickness modes, namely the B-mode and the C-mode. Because of the nature of the difference between the B- and C-modes, the B-mode may be used as an indication of the resonator temperature in order to compensate the C-mode frequency signal. A digital technique for temperature compensation by using the crystal itself as a sensor and a feedback loop varies the heater on the surface of the crystal. The temperature sensor compensation system contains a quartz resonator with a heater affixed thereon. The resonator is arranged as part of the oscillator to generate both B-mode and C-mode frequency signals. The C-mode signal is used as a time standard or frequency reference. Initially, the frequency of the B-mode is counted. The count is started at the same time the frequency count of the C-mode is initiated. The C-mode is then counted to a predetermined frequency value. When the predetermined count is reached for the C-mode, a signal is issued to stop the count of the B-mode frequency. The eight least significant bits of the resultant B-mode count are passed to a D-to-A converter and then used to control a switching regulator which, in turn, alters the temperature of the heater disposed on the crystal resonator. This change in temperature alters the B-mode frequency and, thus, provides a feedback loop to stabilize the C-mode frequency signal.
Inventors
- 👤 Leslie C. Hurley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:05
CPC Classifications
H; H03; H03L; H03L1/00; H03L1/02; H03L1/022; H03L1/023; H03L1/025
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
105 words
A circuit for controlling an output of a dual-mode oscillator including a crystal resonator, wherein the output of the dual-mode oscillator comprises a first signal and a second signal, comprising: first counting means for counting in accordance with the first signal to produce a first output defining a time period; second counting means for counting in accordance with the second signal for the time period defined by the first output to produce a second output defining a temperature of the crystal resonator; and processing means for processing the second output to derive a temperature control signal for selectively adjusting the temperature of the crystal resonator.
Claim 2
Dependent Claim
105 words
A circuit for controlling an output of a dual-mode oscillator including a crystal resonator, wherein the output of the dual-mode oscillator comprises a first signal and a second signal, comprising: first counting means for counting in accordance with the first signal to produce a first output defining a time period; second counting means for counting in accordance with the second signal for the time period defined by the first output to produce a second output defining a temperature of the crystal resonator; and processing means for processing the second output to derive a temperature control signal for selectively adjusting the temperature of the crystal resonator.
Claim 3
Dependent Claim
30 words
The circuit of claim 1, further comprising: heating secured to said resonator for altering the temperature of said resonator in response to said temperature control signal from said processing means.
Claim 4
Dependent Claim
69 words
The circuit of claim 2, further comprising: override means for determining when said temperature of the crystal resonator is higher or lower than predetermined upper and lower limits; and means for maximizing said temperature control signal when said temperature of said crystal resonator is lower than said lower limit and for minimizing said temperature control signal when said temperature of said crystal resonator is higher than said upper limit.
Claim 5
Dependent Claim
16 words
The circuit of claim 3, wherein said minimum value of said temperature control signal is zero.
Claim 6
Dependent Claim
42 words
The circuit of claim 1, wherein said second counting means includes means for producing said second output in digital form, and said processing means includes means for converting said second output in digital form into said temperature control signal in analog form.
Claim 7
Dependent Claim
112 words
A circuit for controlling an output of a dual-mode oscillator that includes an SC-cut crystal resonator, wherein the output of the dual-oscillator comprises a B-mode frequency signal and a C-mode frequency signal, said circuit comprising: first counting means for counting in accordance with the C-mode frequency signal to produce a first output defining a time period; second counting means for counting in accordance with the B-mode frequency signal for the time period defined by the first output to produce a second output defining a temperature of the crystal resonator; and processing means for processing the second output to derive a temperature control signal for selectively adjusting the temperature of the crystal resonator.
Claim 8
Dependent Claim
112 words
A circuit for controlling an output of a dual-mode oscillator that includes an SC-cut crystal resonator, wherein the output of the dual-oscillator comprises a B-mode frequency signal and a C-mode frequency signal, said circuit comprising: first counting means for counting in accordance with the C-mode frequency signal to produce a first output defining a time period; second counting means for counting in accordance with the B-mode frequency signal for the time period defined by the first output to produce a second output defining a temperature of the crystal resonator; and processing means for processing the second output to derive a temperature control signal for selectively adjusting the temperature of the crystal resonator.
Claim 9
Dependent Claim
30 words
The circuit of claim 6, further comprising a heating means secured to said resonator for altering the temperature of said resonator in response to said signal from said processing means.
Claim 10
Dependent Claim
69 words
The circuit of claim 7, further comprising: override means for determining when said temperature of the crystal resonator is higher or lower than predetermined upper and lower limits; and means for maximizing said temperature control signal when said temperature of said crystal resonator is lower than said lower limit and for minimizing said temperature control signal when said temperature of said crystal resonator is higher than said upper limit.
Claim 11
Dependent Claim
16 words
The circuit of claim 8, wherein said minimum value of said temperature control signal is zero.
Claim 12
Dependent Claim
42 words
The circuit of claim 6, wherein said second counting means includes means for producing said second output in digital form, and mail processing means includes means for converting said second output in digital form into said temperature control signal in analog form.
Claim 13
Independent Claim
132 words
A system for frequency control in an SC-cut quartz crystal resonator, said system comprising: an electrically operated heating means secured to said crystal; a dual-mode crystal oscillator operatively connected to said crystal resonator for producing a B-mode frequency signal and a C-mode frequency signal; first counting means for counting the frequency of said B-mode signal; second counting means for counting the frequency of said C-mode signal to a predetermined frequency value; means for causing said first counting means to stop counting when said second counting means reaches said predetermined frequency value; and means responsive to the count of said stopped first counting means for controlling said heating means, wherein the change in the temperature of said crystal resonator alters the B-mode frequency signal resulting in a stabilization of said C-mode frequency signal.
Claim 14
Independent Claim
132 words
A system for frequency control in an SC-cut quartz crystal resonator, said system comprising: an electrically operated heating means secured to said crystal; a dual-mode crystal oscillator operatively connected to said crystal resonator for producing a B-mode frequency signal and a C-mode frequency signal; first counting means for counting the frequency of said B-mode signal; second counting means for counting the frequency of said C-mode signal to a predetermined frequency value; means for causing said first counting means to stop counting when said second counting means reaches said predetermined frequency value; and means responsive to the count of said stopped first counting means for controlling said heating means, wherein the change in the temperature of said crystal resonator alters the B-mode frequency signal resulting in a stabilization of said C-mode frequency signal.
Claim 15
Dependent Claim
45 words
The system of claim 11, wherein said first counting means comprises a first binary counter with a clock input for receiving said B-mode frequency signal, and said second counting means comprises a second binary counter with a clock input for receiving said C-mode frequency signal.
Claim 16
Dependent Claim
15 words
The system of claim 11, further comprising an overriding means for deactivating said heating means.
Claim 17
Dependent Claim
19 words
The system of claim 13, said overriding means further comprising means for operating said heating means at full power.
Claim 18
Independent Claim
96 words
A method for controlling an output of a dual-mode oscillator including a crystal resonator, wherein the output of the dual-mode oscillator comprises a first signal and a second signal, comprising the steps of: counting in accordance with the first signal to produce a first output defining a time period; counting in accordance with the second signal for the time period defining the first output to produce a second output defining a temperature of the crystal resonator; and processing the second output to derive a temperature control signal for selectively adjusting the temperature of the crystal resonator.
Claim 19
Independent Claim
96 words
A method for controlling an output of a dual-mode oscillator including a crystal resonator, wherein the output of the dual-mode oscillator comprises a first signal and a second signal, comprising the steps of: counting in accordance with the first signal to produce a first output defining a time period; counting in accordance with the second signal for the time period defining the first output to produce a second output defining a temperature of the crystal resonator; and processing the second output to derive a temperature control signal for selectively adjusting the temperature of the crystal resonator.
Claim 20
Dependent Claim
27 words
The method of claim 15, further comprising the step of altering the temperature of a surface of the crystal resonator in response to the temperature control signal.
Claim 21
Dependent Claim
66 words
The method of claim 16, further comprising the steps of: determining when the temperature of the crystal resonator is higher or lower than predetermined upper and lower limits; and maximizing the temperature control signal when said temperature of the crystal resonator is lower than the lower limit and minimizing the temperature control signal when the temperature of the crystal resonator is higher than said upper limit.
Claim 22
Dependent Claim
16 words
The method of claim 17, wherein the minimum value of the temperature control signal is zero.
References Cited (Backward Citations)
US3322981A
Cited
US3414794A
Cited
US3463945A
Cited
US3826931A
Cited
US3553602A
Cited
US3561832A
Cited
US3882332A
Cited
US3967143A
Cited
US4039969A
Cited
US4079280A
Cited
US4215308A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-01 | 1994-10-01 | 1995-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-01 | 1998-10-01 | 1999-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-01 | 2002-10-01 | 2003-04-02 | $7700.00 | Window Closed / Lapsed |