US4906944A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrator controlled time compensated clock oscillator
Assignee: Boeing North American Inc
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Filing: 1988-08-17
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Granted: 1990-03-06
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Expires: 2008-08-17
Abstract
Abstract A time compensated clock oscillator (TCCO) is provided with an integrator to produce stability of the output frequency. The integrator is connected between the D/A converter and the voltage controlled crystal oscillator (VCXO) of the TCCO. The output frequency of the VCXO is fed back to a frequency counter, which samples the output, determines its average frequency, and compares it with a reference frequency. A microprocessor corrects the reference frequency for temperature changes, determines the output frequency error, calculates the output frequency drift rate, and provides a digital correction signal. The D/A converter converts the digital correction signal to an input voltage for the integrator. The integrator produces a ramp-shaped control voltage for input to the VCXO. Because the control voltage produced by the integrator changes smoothly over the interval between samples by the frequency counter, the output frequency drift rate of the VCXO is continuously corrected to produce improved short-term frequency stability.
Inventors
- 👤 Marvin E. Frerking
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:01
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/18; H03L7/181; H03L1/00; H03L1/02; H03L1/022; H03L1/026
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
52 words
A controlled oscillator, comprising: means for generating an output frequency; means for sampling said output frequency; means for analyzing said sampled output frequency to produce a correction voltage; and means for integrating said correction voltage to provide a control signal to said generating means to correct for drift of said output frequency.
Claim 2
Dependent Claim
52 words
A controlled oscillator, comprising: means for generating an output frequency; means for sampling said output frequency; means for analyzing said sampled output frequency to produce a correction voltage; and means for integrating said correction voltage to provide a control signal to said generating means to correct for drift of said output frequency.
Claim 3
Dependent Claim
20 words
The controlled oscillator of claim 1, wherein said means for generating an output frequency comprises a voltage controlled crystal oscillator.
Claim 4
Dependent Claim
26 words
The controlled oscillator of claim 1, wherein said sampling means comprises a frequency counter that receives said output frequency as part of a feedback control loop.
Claim 5
Dependent Claim
28 words
The controlled oscillator of claim 1, wherein said analyzing means comprises a microprocessor that receives inputs from a temperature sensor, a temperature correction memory, and said sampling means.
Claim 6
Dependent Claim
20 words
The controlled oscillator of claim 1, wherein said sampling means receives a reference frequency for comparison with said output frequency.
Claim 7
Dependent Claim
26 words
The controlled oscillator of claim 1, wherein said control signal provided by said integrating means is a ramp-shaped signal that provides stability of said output frequency.
Claim 8
Dependent Claim
85 words
A time compensated clock oscillator, comprising: a voltage controlled oscillator for generating an output frequency; a frequency counter for sampling said output frequency and comparing said sampled frequency with a reference frequency; a microprocessor for receiving inputs from a temperature sensor, a temperature correction memory, and said frequency counter; said microprocessor analyzing said inputs and generating a correction voltage; and an integrator for receiving said correction voltage and providing a control voltage to said voltage controlled oscillator to correct for drift of said output frequency.
Claim 9
Dependent Claim
85 words
A time compensated clock oscillator, comprising: a voltage controlled oscillator for generating an output frequency; a frequency counter for sampling said output frequency and comparing said sampled frequency with a reference frequency; a microprocessor for receiving inputs from a temperature sensor, a temperature correction memory, and said frequency counter; said microprocessor analyzing said inputs and generating a correction voltage; and an integrator for receiving said correction voltage and providing a control voltage to said voltage controlled oscillator to correct for drift of said output frequency.
Claim 10
Dependent Claim
36 words
The time compensated clock oscillator of claim 7, wherein said microprocessor calculates a frequency error and drift rate of said output frequency and generates said correction voltage to compensate for said frequency error and drift rate.
Claim 11
Dependent Claim
23 words
The time compensated clock oscillator of claim 8, wherein said control voltage is a ramp-shaped signal that provides stability of said output frequency.
Claim 12
Independent Claim
63 words
A method of controlling a variable output frequency, comprising the steps of: generating the output frequency; sampling the output frequency; comparing said sampled frequency with a reference frequency; analyzing said sampled and compared frequency to produce a correction factor; integrating said correction factor to provide a ramped control input; and providing said ramped control input to compensate for variations of the output frequency.
Claim 13
Independent Claim
63 words
A method of controlling a variable output frequency, comprising the steps of: generating the output frequency; sampling the output frequency; comparing said sampled frequency with a reference frequency; analyzing said sampled and compared frequency to produce a correction factor; integrating said correction factor to provide a ramped control input; and providing said ramped control input to compensate for variations of the output frequency.
Claim 14
Dependent Claim
33 words
The metehod of claim 10, further comprising the step of providing a voltage controlled crystal oscillator (VCXO) for generating the output frequency, said VCXO being subject to a frequency error and drift rate.
Claim 15
Dependent Claim
38 words
The method of claim 11, wherein analyzing said sampled and compared frequency produces a correction voltage and integrating said correction voltage provides a ramped control voltage that compensates for said frequency error and drift rate of said VCXO.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-05 | 1993-09-04 | 1994-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-05 | 1997-09-04 | 1998-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-05 | 2001-09-04 | 2002-03-06 | $7700.00 | Window Closed / Lapsed |