US4718073A
Expired / Lapsed
US
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Demodulator for facsimile equipment
Assignee: Hitachi Ltd
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Filing: 1986-07-03
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Granted: 1988-01-05
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Expires: 2006-07-03
Abstract
Abstract A demodulator for facsimile equipment in which there is provided a memory for storing equalizer coefficients of an automatic equalizer and a divergence detector for detecting divergence of the automatic equalizer, and in which equalizer coefficients of the automatic equalizer established at the beginning of transmission or reception are stored in the memory. In the event of divergence of the automatic equalizer during reception of a subsequent picture data message, the stored equalizer coefficients are re-set in the automatic equalizer.
Inventors
- 👤 Kazuhiko Takaoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:30
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L25/03038; H03; H03H; H03H21/00; H03H21/0012
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
153 words
A demodulator for facsimile equipment, comprising: a demodulating means for demodulating an input signal; an automatic equalizer means for automatically equalizing an output signal provided from said demodulating means; a decision means for making an area decision on an output signal provided from said automatic equalizer means; an error calculating means for performing an error calculation between an output signal provided from said decision means and an output signal from said automatic equalizer means; a memory means for storing equalizer coefficients of said automatic equalizer means; a divergence detecting means for detecting divergence of said automatic equalizer means based on the calculation performed by said error calculating means; and an equalizer coefficient controlling means which, upon detection of divergence of said automatic equalizer means by said divergence detecting means, transfers the equalizer coefficients stored in said memory means to said automatic equalizer means to re-set the equalizer coefficients of the automatic equalizer means.
Claim 2
Dependent Claim
153 words
A demodulator for facsimile equipment, comprising: a demodulating means for demodulating an input signal; an automatic equalizer means for automatically equalizing an output signal provided from said demodulating means; a decision means for making an area decision on an output signal provided from said automatic equalizer means; an error calculating means for performing an error calculation between an output signal provided from said decision means and an output signal from said automatic equalizer means; a memory means for storing equalizer coefficients of said automatic equalizer means; a divergence detecting means for detecting divergence of said automatic equalizer means based on the calculation performed by said error calculating means; and an equalizer coefficient controlling means which, upon detection of divergence of said automatic equalizer means by said divergence detecting means, transfers the equalizer coefficients stored in said memory means to said automatic equalizer means to re-set the equalizer coefficients of the automatic equalizer means.
Claim 3
Dependent Claim
41 words
A demodulator for facsimile equipment according to claim 1, wherein the equalizer coefficients stored in said memory means are equalizer coefficients established in said automatic equalizer means at the time of reception of a training check signal in a facsimile communication.
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) | 1991-01-04 | 1991-07-06 | 1992-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-04 | 1995-07-06 | 1996-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-04 | 1999-07-06 | 2000-01-05 | $7700.00 | Window Closed / Lapsed |