US3843942A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Equalizer for phase modulation communication systems using the instantaneous signal amplitude weighted by signal envelope amplitude distortion as an adjustment control signal
Assignee: International Business Machines Corp
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Filing: 1973-04-25
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Granted: 1974-10-22
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Expires: 1993-04-25
Abstract
Abstract A self-adjustable equalizer for a phase modulation communication system in which the equalizer output signal s is sampled at the modulation rate and weighted by a factor proportional to envelope amplitude distortion dR/R, R being the envelope amplitude at given instants and the product sdR/R being the adjustment control signal. In the preferred embodiment the product of the sign of s and the sign of dR serves as the control or error signal. One implementation frequency translates the equalizer output signal and compares the amplitude of the translated signal with a reference at given instants to determine the sign of dR which is eventually multiplied by the sign of s.
Inventors
- 👤 F Maddens
- 👤 H Nussbaumer
- 👤 J Pierret
- 👤 A Lautier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:46
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/01
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
174 words
A method for equalizing the transmission of a PSK-modulation transmitted data signal onto a transmission medium introducing linear distortions into the transmitted signals, of the type which includes the steps of subjecting the distorted signal received from the transmission medium to the action of a variable transfer function transversal filter so as to obtain an equalized signal, generating an adjustment error signal by comparing the equalized signal to a reference signal at instants determined by a sampling clock producing signals aT the data transmission rate and adjusting the transfer function of the transversal filter so as to tend to minimize said adjustment error signal, characterized in that the step for generating an adjustment error signal includes the following operations: comparing the amplitude of the envelope of said equalized signal at first instants determined by the sampling clock with a reference amplitude so as to generate an envelope error signal; multiplying at second instants determined by the sampling clock said envelope error signal with the equalized signal so as to generate an adjustment error signal.
Claim 2
Independent Claim
174 words
A method for equalizing the transmission of a PSK-modulation transmitted data signal onto a transmission medium introducing linear distortions into the transmitted signals, of the type which includes the steps of subjecting the distorted signal received from the transmission medium to the action of a variable transfer function transversal filter so as to obtain an equalized signal, generating an adjustment error signal by comparing the equalized signal to a reference signal at instants determined by a sampling clock producing signals aT the data transmission rate and adjusting the transfer function of the transversal filter so as to tend to minimize said adjustment error signal, characterized in that the step for generating an adjustment error signal includes the following operations: comparing the amplitude of the envelope of said equalized signal at first instants determined by the sampling clock with a reference amplitude so as to generate an envelope error signal; multiplying at second instants determined by the sampling clock said envelope error signal with the equalized signal so as to generate an adjustment error signal.
Claim 3
Dependent Claim
49 words
A method according to claim 1, characterized in that the step of comparing the envelope amplitude with a reference amplitude includes the detection of the sign of the difference between the two amplitudes, and the generation of an element of information about said sign as the envelope error signal.
Claim 4
Dependent Claim
38 words
A method according to claim 2 characterized in that the multiplication step includes the following operations: taking the sign of the equalized signal, multiplying said sign by said envelope error signal at instants determined by the sampling clock.
Claim 5
Dependent Claim
62 words
A method according to claim 1, characterized in that the step of comparing the equalized signal envelope amplitude with a reference amplitude includes the following operations: transposing said equalized signal into a higher frequency domain to obtain a transposed signal, comparing the amplitude of the envelope of said transposed signal at first instants determined by the sampling clock with a reference amplitude.
Claim 6
Dependent Claim
74 words
A method according to claim 4, characterized in that the step of comparing the amplitude of the envelope of the transposed signal with a reference amplitude includes the following operations: determining a sampling interval from the sampling clock, detecting the first zero-crossing of the transposed signal within said sampling interval, comparing the amplitude of said transposed signal at an instant occurring one quarter of a period of the transposed signal after said first zero-crossing.
Claim 7
Dependent Claim
51 words
A method according to claim 5, characterized in that the step of comparing the amplitude of the envelope of the transposed signal with a reference amplitude further includes the following operations: rectifying said transposed signal before comparing the amplitudes so that the comparison is carried out on the rectified transposed signal.
Claim 8
Dependent Claim
186 words
In a data transmission system using PSK modulation for transmitting data onto a transmission medium introducing linear distortions into the transmitted data and including in the receiving part thereof an equalizer which provides an equalized signal and the transfer function of which may be adjusted so as to minimize an equalizer output error signal, an equalizer output error signal generation device characterized in that it includes: transposition means receiving the equalized signal in order to transpose it to a higher frequency and supply a transposed signal, rectification means receiving said transposed signal in order to supply a rectified transposed signal, comparison means receiving said rectified transposed signal in order to compare it with a reference amplitude signal at determined instants, and generate a binary signal indicative of the sign difference, sign detection means receiving the equalized signal in order to supply a binary signal indicative of the sign of said signal, and binary multiplication means receiving the signal generated by the comparison means and the signal generated by the sign detection means in order to generate an error signal in the form of a binary level.
Claim 9
Dependent Claim
186 words
In a data transmission system using PSK modulation for transmitting data onto a transmission medium introducing linear distortions into the transmitted data and including in the receiving part thereof an equalizer which provides an equalized signal and the transfer function of which may be adjusted so as to minimize an equalizer output error signal, an equalizer output error signal generation device characterized in that it includes: transposition means receiving the equalized signal in order to transpose it to a higher frequency and supply a transposed signal, rectification means receiving said transposed signal in order to supply a rectified transposed signal, comparison means receiving said rectified transposed signal in order to compare it with a reference amplitude signal at determined instants, and generate a binary signal indicative of the sign difference, sign detection means receiving the equalized signal in order to supply a binary signal indicative of the sign of said signal, and binary multiplication means receiving the signal generated by the comparison means and the signal generated by the sign detection means in order to generate an error signal in the form of a binary level.
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) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |