US5732339A
Expired / Lapsed
US
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Frequency offset correction
Assignee: Alcatel CIT SA
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Filing: 1995-10-20
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Granted: 1998-03-24
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Expires: 2015-10-20
Abstract
Abstract In a method and a device for correcting a frequency offset between a receive signal and a reference signal, the receive signal, being fed to a frequency converter which also receives a conversion signal in order to produce a transposed signal, the conversion signal is produced by a local oscillator in response to a control signal. The device initializes the control signal according to the reference signal. An estimator receives the transposed signal and the control signal and produces repetitively an estimate of the frequency offset comprising the sum of a correction value and an adjustment value respectively greater than and less than a predetermined correction threshold. The control signal is modified in response to the correction value. The transposed signal is connected using at least one of the successive estimates.
Inventors
- 👤 Gerard Auvray
- 👤 Olivier Perron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:58
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/02; H03D; H03D3/00; H03D3/007; H03D2200/00; H03D2200/0041; H03D2200/005
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
151 words
Device for correcting a frequency offset between a receive signal and a reference signal, said receive signal being fed to a frequency converter which also receives a conversion signal in order to produce a transposed signal, said conversion signal being produced by a local oscillator in response to a control signal, said device comprising: means for initializing said control signal according to said reference signal; estimator means which receive said transposed signal and said control signal to produce repetitively an estimate of said frequency offset, said estimate comprising the sum of a correction value and an adjustment value, said correction value being greater than or equal to a predetermined correction threshold and said adjustment value being less than said predetermined correction threshold; means for modifying said control signal in response to said correction value; and means for correcting said transposed signal by means of at least one of said successive estimates.
Claim 2
Dependent Claim
151 words
Device for correcting a frequency offset between a receive signal and a reference signal, said receive signal being fed to a frequency converter which also receives a conversion signal in order to produce a transposed signal, said conversion signal being produced by a local oscillator in response to a control signal, said device comprising: means for initializing said control signal according to said reference signal; estimator means which receive said transposed signal and said control signal to produce repetitively an estimate of said frequency offset, said estimate comprising the sum of a correction value and an adjustment value, said correction value being greater than or equal to a predetermined correction threshold and said adjustment value being less than said predetermined correction threshold; means for modifying said control signal in response to said correction value; and means for correcting said transposed signal by means of at least one of said successive estimates.
Claim 3
Dependent Claim
28 words
The device according to claim 1 wherein, said conversion signal comprises discrete frequencies regularly spaced by an incremental value, said correction threshold being equal to said incremental value.
Claim 4
Dependent Claim
17 words
The device according to claim 2 wherein said correction value is a multiple of said incremental value.
Claim 5
Dependent Claim
49 words
The device according to claim 1, wherein said estimator means effects a first estimate using a first set of parameters dependent on the maximum offset between said reference signal and said receive signal and effects a subsequent estimate using a second set of parameters dependent on said correction threshold.
Claim 6
Dependent Claim
24 words
The device according to claim 4 wherein different frequencies of said receive signal are used for said first estimate and for said subsequent estimate.
Claim 7
Dependent Claim
43 words
The device according to claim 4 wherein, said receive signal is in the form of a succession of bursts each comprising a training sequence and a data sequence, one of said estimates being effected on said training sequence to correct said data sequence.
Claim 8
Dependent Claim
30 words
The device according to claim 1 wherein said estimates are obtained by means of the autocorrelation function of a known sequence of the transmit signal corresponding to said receive signal.
Claim 9
Dependent Claim
125 words
Method of correcting a frequency offset between a receive signal and a conversion signal comprising the following steps: converting said receive signal by means of a conversion signal to produce a transposed signal; a first estimate of said frequency offset; modifying said conversion signal when said first estimate exceeds a predetermined correction threshold, said first estimate comprising a sum of a correction value which is a multiple of said predetermined correction threshold and an adjustment value which is less than said predetermined correction threshold, said modifying step including modifying said conversion signal based on said correction value; producing an estimate of the residual frequency offset between said receive signal and said modified conversion signal; and correcting said transposed signal by means of said residual offset.
Claim 10
Dependent Claim
125 words
Method of correcting a frequency offset between a receive signal and a conversion signal comprising the following steps: converting said receive signal by means of a conversion signal to produce a transposed signal; a first estimate of said frequency offset; modifying said conversion signal when said first estimate exceeds a predetermined correction threshold, said first estimate comprising a sum of a correction value which is a multiple of said predetermined correction threshold and an adjustment value which is less than said predetermined correction threshold, said modifying step including modifying said conversion signal based on said correction value; producing an estimate of the residual frequency offset between said receive signal and said modified conversion signal; and correcting said transposed signal by means of said residual offset.
Claim 11
Dependent Claim
45 words
The device according to claim 1, wherein said transposed signal comprises a plurality of digital samples, said means for correcting said transposed signal calculating corrected digital samples by applying a correction function to each of said digital samples, thereby effecting correction of the transposed signal.
Claim 12
Dependent Claim
18 words
The device according to claim 9, wherein said correction function adjusts the relative phase between two consecutive samples.
Claim 13
Dependent Claim
30 words
The device according to claim 1, wherein the means for modifying said control signal effects coarse frequency adjustment, and said means for correcting said transposed signal effects fine frequency adjustment.
Claim 14
Dependent Claim
42 words
The method according to claim 8, wherein said transposed signal comprises a plurality of digital samples, the correcting step comprising calculating corrected digital samples by applying a correction function to each of said digital samples, thereby effecting correction of the transposed signal.
Claim 15
Dependent Claim
18 words
The method according to claim 12, wherein said correction function adjusts the relative phase between two consecutive samples.
Claim 16
Independent Claim
171 words
A device for correcting a frequency offset between a receive signal and a reference signal, said receive signal being fed to a frequency converter which also receives a conversion signal in order to produce a transposed signal, said conversion signal being produced by a local oscillator in response to a control signal, said device comprising: means for initializing said control signal according to said reference signal; estimator means which receives said transposed signal and repetitively produces an estimate of said frequency offset; means for modifying said control signal when said estimate exceeds a predetermined correction threshold, said estimate comprising a sum of a correction value which is a multiple of said predetermined correction threshold and an adjustment value which is less than said predetermined correction threshold, said means for modifying modifying said control signal based on said correction value; and means for correcting said transposed signal produced by said frequency converter by calculating a corrected transposed signal from said transposed signal and from one of said estimate and said adjustment value.
Claim 17
Independent Claim
171 words
A device for correcting a frequency offset between a receive signal and a reference signal, said receive signal being fed to a frequency converter which also receives a conversion signal in order to produce a transposed signal, said conversion signal being produced by a local oscillator in response to a control signal, said device comprising: means for initializing said control signal according to said reference signal; estimator means which receives said transposed signal and repetitively produces an estimate of said frequency offset; means for modifying said control signal when said estimate exceeds a predetermined correction threshold, said estimate comprising a sum of a correction value which is a multiple of said predetermined correction threshold and an adjustment value which is less than said predetermined correction threshold, said means for modifying modifying said control signal based on said correction value; and means for correcting said transposed signal produced by said frequency converter by calculating a corrected transposed signal from said transposed signal and from one of said estimate and said adjustment value.
Claim 18
Dependent Claim
45 words
The device according to claim 14, wherein said transposed signal comprises a plurality of digital samples, said means for correcting said transposed signal calculating corrected digital samples by applying a correction function to each of said digital samples, thereby effecting correction of the transposed signal.
Claim 19
Independent Claim
113 words
A method of correcting a frequency offset between a receive signal and a conversion signal comprising the steps of: converting said receive signal by means of a conversion signal to produce a transposed signal; producing an estimate of said frequency offset; modifying said conversion signal when said estimate exceeds a predetermined correction threshold, said estimate comprising a sum of a correction value which is a multiple of said predetermined correction threshold and an adjustment value which is less than said predetermined correction threshold, said modifying step including modifying said control signal based on said correction value; and calculating a corrected transposed signal from said transposed signal and from a function of said estimate.
Claim 20
Independent Claim
113 words
A method of correcting a frequency offset between a receive signal and a conversion signal comprising the steps of: converting said receive signal by means of a conversion signal to produce a transposed signal; producing an estimate of said frequency offset; modifying said conversion signal when said estimate exceeds a predetermined correction threshold, said estimate comprising a sum of a correction value which is a multiple of said predetermined correction threshold and an adjustment value which is less than said predetermined correction threshold, said modifying step including modifying said control signal based on said correction value; and calculating a corrected transposed signal from said transposed signal and from a function of said estimate.
Claim 21
Dependent Claim
42 words
The method according to claim 16, wherein said transposed signal comprises a plurality of digital samples, said calculating step comprising calculating corrected digital samples by applying a correction function to each of said digital samples, thereby effecting correction of the transposed signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-03-23 | 2001-09-22 | 2002-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-23 | 2005-09-22 | 2006-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-23 | 2009-09-22 | 2010-03-24 | $7700.00 | Window Closed / Lapsed |