US5084902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Jitter canceller with an initial value setting circuit for an adaptive filter
Assignee: NEC Corp
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Filing: 1990-03-14
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Granted: 1992-01-28
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Expires: 2010-03-14
Abstract
Abstract A jitter canceller cancels time-variant signals in telephone lines resulting from 50 or 60 Hz commercial power sources which a phase locked loop will fail to absorb. The jitter canceller uses an adaptive filter having a tap coefficient which is not reset to "0" and forced to converge before a data transmission allowing use with telephone lines with multiple modems connected to a single line. The jitter canceller uses a phase rotating circuit, two phase difference detectors, and the adaptive filter to rotate the phase of an incoming signal by a phase predicted by the adaptive filter in order to cancel jittering.
Inventors
- 👤 Yoshihisa Aotani
- 👤 Masayuki Yamada
- 👤 Kazushi Norimatsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:27
CPC Classifications
H; H03; H03L; H03L7/00; H04; H04B; H04B1/00; H04B1/06; H04B1/10; H04B1/12; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/233; H04L27/2332; H04L27/0014; H04L2027/0024; H04L2027/0026; H04L2027/003; H04L2027/0036; H04L2027/0044; H04L2027/0053; H04L2027/0057; H04L2027/0063; H04L2027/0069
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
136 words
A jitter canceller comprising: phase rotating means for supplying a phase-rotated received signal by rotating a received complex baseband signal by a prescribed phase; a decision circuit for discriminating a received symbol from said phase-rotated received signal and supplying a discriminated symbol; first phase detecting means for extracting a phase error between said discriminated signal and said received complex baseband signal and supplying a first phase error signal; second phase detecting means for extracting a phase error between said discriminated signal and said phase-rotated received signal and supplying a second phase error signal; and adaptive filter responsive to said first and second phase error signals for generating said prescribed phase; and coefficient setting means responsive to a clear signal supplied from outside for setting a prescribed filter coefficient as a tap coefficient of said adaptive filter.
Claim 2
Dependent Claim
136 words
A jitter canceller comprising: phase rotating means for supplying a phase-rotated received signal by rotating a received complex baseband signal by a prescribed phase; a decision circuit for discriminating a received symbol from said phase-rotated received signal and supplying a discriminated symbol; first phase detecting means for extracting a phase error between said discriminated signal and said received complex baseband signal and supplying a first phase error signal; second phase detecting means for extracting a phase error between said discriminated signal and said phase-rotated received signal and supplying a second phase error signal; and adaptive filter responsive to said first and second phase error signals for generating said prescribed phase; and coefficient setting means responsive to a clear signal supplied from outside for setting a prescribed filter coefficient as a tap coefficient of said adaptive filter.
Claim 3
Dependent Claim
37 words
A jitter canceller, as claimed in claim 1, wherein a value which will so determine the frequency characteristic of said adaptive filter as to pass only a single sine wave is used as said prescribed filter coefficient.
Claim 4
Independent Claim
121 words
A method for jitter canceling comprising the following steps: supplying a phase-rotated received signal by rotating a received complex baseband signal by a prescribed phase; discriminating a received symbol from said phase-rotated received signal and supplying a discriminated symbol; extracting a first phase error between said discriminated signal and said received complex baseband signal and supplying a first phase error signal; extracting a second phase error between said discriminated signal and said phase-rotated received signal and supplying a second phase error signal; generating said prescribed phase from said first and second phase error signals using an adaptive filter; and responding to a clear signal supplied from outside by setting a prescribed filter coefficient as a tap coefficient of said adaptive filter.
Claim 5
Independent Claim
121 words
A method for jitter canceling comprising the following steps: supplying a phase-rotated received signal by rotating a received complex baseband signal by a prescribed phase; discriminating a received symbol from said phase-rotated received signal and supplying a discriminated symbol; extracting a first phase error between said discriminated signal and said received complex baseband signal and supplying a first phase error signal; extracting a second phase error between said discriminated signal and said phase-rotated received signal and supplying a second phase error signal; generating said prescribed phase from said first and second phase error signals using an adaptive filter; and responding to a clear signal supplied from outside by setting a prescribed filter coefficient as a tap coefficient of said adaptive filter.
Claim 6
Dependent Claim
137 words
A jitter canceller comprising: phase rotating circuit for supplying a phase-rotated received signal by rotating a received complex baseband signal by a prescribed phase; a decision circuit for discriminating a received symbol from said phase-rotated received signal and supplying a discriminated symbol; first phase difference detector for extracting a phase error between said discriminated signal and said received complex baseband signal and supplying a first phase error signal; second phase different detector for extracting a phase error between said discriminated signal and said phase-rotated received signal and supplying a second phase error signal; an adaptive filter responsive to said first and second phase error signals for generating said prescribed phase; and a coefficient updating circuit responsive to a clear signal supplied from outside for setting a prescribed filter coefficient as a tap coefficient of said adaptive filter.
Claim 7
Dependent Claim
137 words
A jitter canceller comprising: phase rotating circuit for supplying a phase-rotated received signal by rotating a received complex baseband signal by a prescribed phase; a decision circuit for discriminating a received symbol from said phase-rotated received signal and supplying a discriminated symbol; first phase difference detector for extracting a phase error between said discriminated signal and said received complex baseband signal and supplying a first phase error signal; second phase different detector for extracting a phase error between said discriminated signal and said phase-rotated received signal and supplying a second phase error signal; an adaptive filter responsive to said first and second phase error signals for generating said prescribed phase; and a coefficient updating circuit responsive to a clear signal supplied from outside for setting a prescribed filter coefficient as a tap coefficient of said adaptive filter.
References Cited (Backward Citations)
US4639939A
Cited
US4926499A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-01-27 | 1995-07-29 | 1996-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-27 | 1999-07-29 | 2000-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-27 | 2003-07-29 | 2004-01-28 | $7700.00 | Window Closed / Lapsed |