Patent US3745463A successfully refreshed from Google Patents.
US3745463A
Expired / Lapsed
US
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Coded equalizer
Assignee: United States Department of the Army
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Filing: 1971-07-08
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Granted: 1973-07-10
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Expires: 1991-07-08
Abstract
Abstract A digital information receiver having a tapped delay line equalizer for reducing intersymbol interference caused by a linear time dispersive transmission channel. The tapped delay line equalizer includes a plurality of amplifiers the gains of which are adjusted such that the combined response of the equalizer and channel approximates a multi-element coded digital signal which has the same number of levels as the signals to be transmitted, has the same number of elements as the channel response signal, and wherein the mean squared error between the combined channel and equalizer response signal and the channel response signal is a minimum. The output of the equalizer is connected to a decoder via a quantizer for decoding the transformed signal.
Inventors
- 👤 T Klein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:59
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L25/03038
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
220 words
In a digital communication system having a digital transmitter means for transmitting a digital signal and coupled to a digital transmission channel which time disperses said transmitted digital signal according to a known response between the channel input and output, a digital receiver coupled to the output of said channel, said receiver comprising: a tapped delay line having an input and a plurality of tap outputs and wherein the time delay between successive ones of said tap outputs is equal to one baud; a plurality of gain means each connected to one of said tap outputs; the gains of said gain means having values such that, the combined channel and receiver response is substantially a multi-element coded digital signal, and the mean squared error between said channel response and said combined channel and receiver response is a minimum; summing means connected to the output of said gain means for summing the instantaneous amplitudes of said outputs of said gain means once during each said baud; quantizer means connected to the output of said summing means for converting the output thereof into a digital signal by quantizing the amplitudes of the output of said summing means; and digital decoder means connected to the output of said quantizer means for converting the output of said quantizer means into said transmitted digital signal.
Claim 2
Dependent Claim
220 words
In a digital communication system having a digital transmitter means for transmitting a digital signal and coupled to a digital transmission channel which time disperses said transmitted digital signal according to a known response between the channel input and output, a digital receiver coupled to the output of said channel, said receiver comprising: a tapped delay line having an input and a plurality of tap outputs and wherein the time delay between successive ones of said tap outputs is equal to one baud; a plurality of gain means each connected to one of said tap outputs; the gains of said gain means having values such that, the combined channel and receiver response is substantially a multi-element coded digital signal, and the mean squared error between said channel response and said combined channel and receiver response is a minimum; summing means connected to the output of said gain means for summing the instantaneous amplitudes of said outputs of said gain means once during each said baud; quantizer means connected to the output of said summing means for converting the output thereof into a digital signal by quantizing the amplitudes of the output of said summing means; and digital decoder means connected to the output of said quantizer means for converting the output of said quantizer means into said transmitted digital signal.
Claim 3
Dependent Claim
34 words
The system according to claim 1 and wherein said values of said gains are such that the number of digital elements in said channel response and said combined channel and receiver responses are equal.
Claim 4
Dependent Claim
34 words
The system according to claim 2 and wherein said values of said gains are such that the number of levels in said transmitted digital signal and said coMbined channel and receiver response are equal.
Claim 5
Dependent Claim
31 words
The system according to claim 3 and wherein said values of said gains are such that the elements of said coded digital signal are the elements of an error correcting code.
Claim 6
Dependent Claim
69 words
The system according to claim 1 and wherein the channel response is such that a single digital element is dispersed over n bauds according to a linear transformation represented by a matrix C; and said values of said gains, represented by a vector q, are such that said coded digital signal has n digital elements represented by the vector r and the following relationship is satisfied: q (CTC) 1CTr.
Claim 7
Dependent Claim
32 words
The system according to claim 5 and wherein said values of said gains are such that the number of levels in said transmitted digital signal and said coded digital signal are equal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |