US4355402A
Expired / Lapsed
US
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Data modem false equilibrium circuit
Assignee: Racal Data Communications Inc
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Filing: 1978-10-19
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Granted: 1982-10-19
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Expires: 1998-10-19
Abstract
Abstract Circuitry for detecting and correcting false equilibrium conditions generated in data modems by sudden changes in gain of an associated transmission system including a false gain detector which detects a low rate of production of symbols of largest magnitude and triggers a final gain circuit which initially jumps the overall system gain and thereafter adaptively adjusts the gain jump to the correct value.
Inventors
- 👤 Philip F. Kromer, III
- 👤 Ran F. Chiu
- 👤 Ming L. Kao
- 👤 Henry H. Parrish
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:27
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3036; H04; H04L; H04L1/00; H04L1/20; H04L1/206; H04L27/00; H04L27/02; H04L27/08; H04L27/32; H04L27/34; H04L27/38; H04L27/3809
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
82 words
In a data modem having a receiver gain and means for detecting symbols of a plurality of discrete magnitudes from an input signal and for providing an output indicative of the symbols detected, the apparatus comprising: means responsive to the symbol detecting means for detecting a below-average rate of detection of symbols of one of said magnitudes and producing a trigger signal indicative of the detection of said below-average rate; and means responsive to said trigger signal for modifying the receiver gain.
Claim 2
Dependent Claim
82 words
In a data modem having a receiver gain and means for detecting symbols of a plurality of discrete magnitudes from an input signal and for providing an output indicative of the symbols detected, the apparatus comprising: means responsive to the symbol detecting means for detecting a below-average rate of detection of symbols of one of said magnitudes and producing a trigger signal indicative of the detection of said below-average rate; and means responsive to said trigger signal for modifying the receiver gain.
Claim 3
Dependent Claim
29 words
The apparatus of claim 1 wherein said means responsive to said trigger signal is further responsive to said input signal for increasing the gain applied to said input signal.
Claim 4
Dependent Claim
34 words
The apparatus of claim 1 or 2 wherein the magnitude of the symbol detected by said means for detecting a below-average rate of detection is the largest magnitude produced by said symbol detecting means.
Claim 5
Dependent Claim
32 words
The apparatus of claim 2 wherein said gain increasing means in response to said trigger signal provides an initial jump in said gain and then adaptively reduces its contribution to said gain.
Claim 6
Dependent Claim
57 words
The apparatus of claim 1 wherein said below-average rate detecting means includes an adder means responsive to the detection and non-detection by the symbol detecting means of symbols of said one magnitude and a register means whose contents are controlled by said adder means, said adder means also being responsive to the contents of said register means.
Claim 7
Dependent Claim
66 words
The apparatus of claim 2 wherein said means responsive to said trigger signal comprises: means for multiplying said input signal by a gain factor; means for producing an error signal indicative of the departure of said input signal from a desired gain value; and means for jumping said gain factor in response to said trigger signal and reducing said gain in response to said error signal.
Claim 8
Dependent Claim
24 words
The apparatus of claim 6 wherein said producing means includes means for multiplying the input to said symbol detecting means by the output thereof.
Claim 9
Dependent Claim
80 words
In a modem having a receiver system gain and a decision means operative on the output of an equalizer means to resolve said output into one of a plurality of data symbols and subject to a false equilibrium condition wherein the system gain is reduced to a level of operation, the resolution of data symbols by said decision means is incorrect, the improvement comprising: means responsive to the resolution of data symbols for detecting and correcting said false equilibrium condition.
Claim 10
Dependent Claim
80 words
In a modem having a receiver system gain and a decision means operative on the output of an equalizer means to resolve said output into one of a plurality of data symbols and subject to a false equilibrium condition wherein the system gain is reduced to a level of operation, the resolution of data symbols by said decision means is incorrect, the improvement comprising: means responsive to the resolution of data symbols for detecting and correcting said false equilibrium condition.
Claim 11
Dependent Claim
25 words
The apparatus of claim 8 wherein said means for detecting and correcting detects false equilibrium by detecting an incorrect average production of said data symbols.
Claim 12
Dependent Claim
25 words
The apparatus of claim 8 or 9 wherein said false equilibrium is corrected by jumping the gain applied to the input to said decision means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-10-18 | 1986-04-19 | 1986-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-18 | 1990-04-19 | 1990-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-18 | 1994-04-19 | 1994-10-19 | $7700.00 | Window Closed / Lapsed |