US5168246A
Expired / Lapsed
US
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Error amplifier for multiple frequency oscillator control
Assignee: First National Bank of Chicago
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Filing: 1991-10-24
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Granted: 1992-12-01
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Expires: 2011-10-24
Abstract
Abstract A multiple frequency scan oscillator control system includes a phase locked loop operative upon a scan oscillator to provide phase and frequency synchronization thereof to a periodic reference signal. A static phase error correction is operative to provide adjustment of the free-running or static frequency of the scan oscillator. An error amplifier includes a pair of intercoupled differential amplifier configurations one having a constant current source and the other having a frequency dependent current source which responds to a frequency dependent bias current to alter amplifier gain. A threshold detection circuit includes a differential amplifier pair coupled to a pair of switching circuits for establishing a threshold action in response to system error voltage to indicate large magnitude error voltages and signal the need for free-running frequency adjustment of the oscillator.
Inventors
- 👤 Kishan R. Pulluru
- 👤 Gopal K. Srivastava
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:19
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085; H03L7/093; H03L7/10; H04; H04N; H04N5/00; H04N5/04; H04N5/05; H04N5/12; H04N5/126
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
96 words
For use in an oscillator system having a reference frequency, an oscillator exhibiting an oscillator frequency, and an oscillator control comparing said oscillator frequency to said reference frequency and producing a comparison-related error signal, an error signal amplifier comprising: amplifying means for amplifying said error signal having a variable signal gain; frequency bias means for varying said amplifier gain in response to a control signal related to said reference frequency; and threshold means responsive to said error signal in excess of a predetermined amplitude to produce an output signal indicative of large magnitude oscillator frequency errors.
Claim 2
Dependent Claim
96 words
For use in an oscillator system having a reference frequency, an oscillator exhibiting an oscillator frequency, and an oscillator control comparing said oscillator frequency to said reference frequency and producing a comparison-related error signal, an error signal amplifier comprising: amplifying means for amplifying said error signal having a variable signal gain; frequency bias means for varying said amplifier gain in response to a control signal related to said reference frequency; and threshold means responsive to said error signal in excess of a predetermined amplitude to produce an output signal indicative of large magnitude oscillator frequency errors.
Claim 3
Dependent Claim
43 words
An error signal amplifier as set forth in claim 1 wherein said oscillator defines a frequency-dependent nonlinear response to said error signal and wherein said control signal varies said signal gain in a compensating substantially inverse frequency-dependent manner to linearize said oscillator control.
Claim 4
Dependent Claim
54 words
An error signal amplifier as set forth in claim 2 wherein said amplifying means include a first differential amplifier having a constant current source and wherein said frequency bias means include a second differential amplifier having inputs coupled to said first differential amplifier and having a variable current source responsive to said control signal.
Claim 5
Dependent Claim
53 words
An error signal amplifier as set forth in claim 3 wherein said threshold means include: a third differential amplifier having an input and a pair of differential outputs; first and second threshold switches coupled to said differential outputs; and means for applying said error signal to said input of said third differential amplifier.
Claim 6
Dependent Claim
135 words
For use in a phase locked loop control system having an oscillator defining a nonlinear frequency-dependent error signal response characteristic, a phase detector for comparing the frequency and phase of said oscillator to a reference sync signal and for producing a corresponding error signal, and filter means for coupling said error signal to an error signal amplifier, said error signal amplifier comprising: amplifying means having a variable signal gain interposed between said filter means and said phase detector; frequency range means for producing a frequency-indicative signal related to the frequency of said reference sync signal; and bias means for varying said signal gain of said amplifying means in response to said frequency-indicative signal to establish a signal gain for said amplifying means which tends to compensate for said error signal response characteristic of said oscillator.
Claim 7
Dependent Claim
135 words
For use in a phase locked loop control system having an oscillator defining a nonlinear frequency-dependent error signal response characteristic, a phase detector for comparing the frequency and phase of said oscillator to a reference sync signal and for producing a corresponding error signal, and filter means for coupling said error signal to an error signal amplifier, said error signal amplifier comprising: amplifying means having a variable signal gain interposed between said filter means and said phase detector; frequency range means for producing a frequency-indicative signal related to the frequency of said reference sync signal; and bias means for varying said signal gain of said amplifying means in response to said frequency-indicative signal to establish a signal gain for said amplifying means which tends to compensate for said error signal response characteristic of said oscillator.
Claim 8
Dependent Claim
38 words
An error signal amplifier as set forth in claim 5 further including: threshold means responsive to said error signal for producing an output signal indicative of error signal magnitudes less than or greater than a predetermined amplitude range.
Claim 9
Dependent Claim
75 words
An error signal amplifier as set forth in claim 6 wherein said amplifying means include: a first differential amplifier having a first pair of differential inputs, a common constant current source and a first pair of differential outputs; and a second differential amplifier having a second pair of inputs coupled to said first pair of outputs, a second pair of outputs one of which is coupled to said oscillator, and a common variable current source.
Claim 10
Dependent Claim
32 words
An error signal amplifier as set forth in claim 7 wherein said bias means include means for coupling at least a portion of said frequency-indicative signal to said common variable current source.
References Cited (Backward Citations)
US4568888A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-12-01 | 1996-06-01 | 1996-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-12-01 | 2000-06-01 | 2000-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-12-01 | 2004-06-01 | 2004-12-01 | $7700.00 | Window Closed / Lapsed |