US5233633A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic frequency control by an adaptive filter
Assignee: Motorola Solutions Inc
•
Filing: 1993-02-09
•
Granted: 1993-08-03
•
Expires: 2013-02-09
Abstract
Abstract The process of the present invention generates an optimum automatic frequency control signal in an apparatus that has a plurality of adaptive algorithms, each adaptive algorithm having a reference signal with an associated frequency dither. The process starts by comparing the performance of each of the plurality of adaptive algorithms. This difference is input to a comparator where it is compared to zero. This delta signal then modifies the numerically controlled oscillator frequency. After several iterations, the frequency offset is reduced to substantially zero.
Inventors
- 👤 Kevin L. Baum
- 👤 Bruce D. Mueller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:52
CPC Classifications
H; H03; H03H; H03H21/00; H03H21/0012; H03H21/0043; H03J; H03J7/00; H03J7/02; H03J7/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
82 words
A method for generating an automatic frequency control signal in an apparatus having a plurality of adaptive filters, each adaptive filter having an adaptive algorithm, a subset number of adapter filters of the plurality of adaptive filters having a reference signal with an associated frequency dither, the method comprising the steps of: generating a difference signal by comparing performances of the subset number of adaptive filters with each other; and adjusting the automatic frequency control signal in response to the difference signal.
Claim 2
Independent Claim
82 words
A method for generating an automatic frequency control signal in an apparatus having a plurality of adaptive filters, each adaptive filter having an adaptive algorithm, a subset number of adapter filters of the plurality of adaptive filters having a reference signal with an associated frequency dither, the method comprising the steps of: generating a difference signal by comparing performances of the subset number of adaptive filters with each other; and adjusting the automatic frequency control signal in response to the difference signal.
Claim 3
Independent Claim
192 words
A method for automatic frequency control in a system having a baseband received signal, an oscillator signal, and a symbol decision signal, the method comprising the steps of: multiplying the baseband received signal with the oscillator signal to produce a first reference signal; multiplying the first reference signal by a first offset signal, having a first magnitude, to produce a second reference signal; multiplying the first reference signal by a second offset signal, having a second magnitude, to produce a third reference signal; generating a first error signal in response to the symbol decision signal and the first reference signal; generating a second error signal in response to the symbol decision signal and the second reference signal; generating a third error signal in response to the symbol decision signal and the third reference signal; estimating a first mean square error in response to the second error signal; estimating a second mean square error in response to the third error signal; subtracting the second mean square error from the first mean square error to produce a mean square error difference; and modifying the oscillator signal in response to the mean square error difference.
Claim 4
Independent Claim
192 words
A method for automatic frequency control in a system having a baseband received signal, an oscillator signal, and a symbol decision signal, the method comprising the steps of: multiplying the baseband received signal with the oscillator signal to produce a first reference signal; multiplying the first reference signal by a first offset signal, having a first magnitude, to produce a second reference signal; multiplying the first reference signal by a second offset signal, having a second magnitude, to produce a third reference signal; generating a first error signal in response to the symbol decision signal and the first reference signal; generating a second error signal in response to the symbol decision signal and the second reference signal; generating a third error signal in response to the symbol decision signal and the third reference signal; estimating a first mean square error in response to the second error signal; estimating a second mean square error in response to the third error signal; subtracting the second mean square error from the first mean square error to produce a mean square error difference; and modifying the oscillator signal in response to the mean square error difference.
Claim 5
Independent Claim
268 words
An apparatus for automatic frequency control in a device having a received signal, oscillating means for generating an oscillator signal, symbol detection means for generating a symbol decision signal, and a plurality of multiplying means for generating a plurality of reference signals, the apparatus comprising: first adaptive filtering means, coupled to the symbol detection means and first multiplying means of the plurality of multiplying means, for generating a first error signal in response to the symbol decision signal and a first reference signal of the plurality of reference signals; second adaptive filtering means, coupled to the symbol detection means and second multiplying means of the plurality of multiplying means, for generating a second error signal in response to the symbol decision signal, the oscillator signal, and the received signal; third adaptive filtering means, coupled to the symbol detection means and third multiplying means of the plurality of multiplying means, for generating a third error signal in response to the symbol decision signal and a second reference signal of the plurality of reference signals; first means for estimating mean square error, coupled to the first adaptive filtering means, for generating a first mean square error estimate; second means for estimating mean square error, coupled to the third adaptive filtering means, for generating a second mean square error estimate; summing means, coupled to the first and second means for estimating mean square error, for producing a difference signal; means for producing a delta signal coupled to the summing means; and accumulation means, coupled to the means for producing a delta signal and the oscillating means, for accumulating the delta signal.
Claim 6
Independent Claim
268 words
An apparatus for automatic frequency control in a device having a received signal, oscillating means for generating an oscillator signal, symbol detection means for generating a symbol decision signal, and a plurality of multiplying means for generating a plurality of reference signals, the apparatus comprising: first adaptive filtering means, coupled to the symbol detection means and first multiplying means of the plurality of multiplying means, for generating a first error signal in response to the symbol decision signal and a first reference signal of the plurality of reference signals; second adaptive filtering means, coupled to the symbol detection means and second multiplying means of the plurality of multiplying means, for generating a second error signal in response to the symbol decision signal, the oscillator signal, and the received signal; third adaptive filtering means, coupled to the symbol detection means and third multiplying means of the plurality of multiplying means, for generating a third error signal in response to the symbol decision signal and a second reference signal of the plurality of reference signals; first means for estimating mean square error, coupled to the first adaptive filtering means, for generating a first mean square error estimate; second means for estimating mean square error, coupled to the third adaptive filtering means, for generating a second mean square error estimate; summing means, coupled to the first and second means for estimating mean square error, for producing a difference signal; means for producing a delta signal coupled to the summing means; and accumulation means, coupled to the means for producing a delta signal and the oscillating means, for accumulating the delta signal.
Claim 7
Dependent Claim
18 words
The apparatus of claim 3 wherein the first, second, and third adaptive filtering means are adaptive channel estimators.
Claim 8
Dependent Claim
17 words
The apparatus of claim 3 wherein the first, second, and third adaptive filtering means are adaptive equalizers.
Claim 9
Independent Claim
175 words
A method for automatic frequency control in a system having a baseband received signal, an oscillator signal, and a symbol decision signal, the method comprising the steps of: multiplying the baseband received signal with the oscillator signal to produce a first reference signal; multiplying the first reference signal by a first offset signal, having a first magnitude, to produce a second reference signal; multiplying the first reference signal by a second offset signal, having a second magnitude, to produce a third reference signal; generating a first error signal in response to the symbol decision signal and the second reference signal; generating a second error signal in response to the symbol decision signal and the third reference signal; estimating a first mean square error in response to the first error signal; estimating a second mean square error in response to the second error signal; subtracting the second mean square error from the first mean square error to produce a means square error difference; and modifying the oscillator signal in response to the mean square error difference.
Claim 10
Independent Claim
175 words
A method for automatic frequency control in a system having a baseband received signal, an oscillator signal, and a symbol decision signal, the method comprising the steps of: multiplying the baseband received signal with the oscillator signal to produce a first reference signal; multiplying the first reference signal by a first offset signal, having a first magnitude, to produce a second reference signal; multiplying the first reference signal by a second offset signal, having a second magnitude, to produce a third reference signal; generating a first error signal in response to the symbol decision signal and the second reference signal; generating a second error signal in response to the symbol decision signal and the third reference signal; estimating a first mean square error in response to the first error signal; estimating a second mean square error in response to the second error signal; subtracting the second mean square error from the first mean square error to produce a means square error difference; and modifying the oscillator signal in response to the mean square error difference.
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) | 1996-08-02 | 1997-02-01 | 1997-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-02 | 2001-02-01 | 2001-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-02 | 2005-02-01 | 2005-08-03 | $7700.00 | Window Closed / Lapsed |