Patent US4037160A successfully refreshed from Google Patents.
US4037160A
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Method and apparatus for adjusting and readjusting an automatic corrector for a data signal transmission system
Assignee: OMNISEC AG TROCKENLOOSTRASSE 91 CH-8105 REGENSDORF SWITZERLAND A Co OF SWITZERLAND
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Filing: 1975-11-25
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Granted: 1977-07-19
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Expires: 1995-11-25
Abstract
Abstract A method of adjusting and readjusting an automatic corrector for a data signal transmission system, the corrector serving to restore pulse-amplitude-modulated signals which have suffered linear distortions in a transmission channel. A transversal filter of the corrector receives during a first adjustment phase a reference signal sequence transmitted over the transmission channel and an identical reference signal produced at the receiving end to produce error signals which serve to adjust the transversal filter coefficients stored in the corrector. The filter coefficients are subdivided into at least two groups and during the first phase one group of filter coefficients is calculated with a more attenuated error signal than the filter coefficients of the other group. In a second adjustment phase the filter coefficients of the transversal filter are readjusted in respect of alterations of the properties of the transmission channel, the error signal formed from the output signal of the transversal filter and the reference values for the latter signal being correlated with the data signal arriving at the input of the transversal filter.
Inventors
- 👤 Predrag Miloradovic
- 👤 Hans Schaffhauser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:01
CPC Classifications
H; H03; H03H; H03H21/00; H03H21/0012; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L25/03038
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
283 words
A method for establishing optimum attenuator settings in a transversal equalizer intended for correction of distortion imposed upon pulse-amplitude-modulated communication signals in passage through a transmission medium comprising in a first phase: a. generating a first reference signal sequence at the transmitting end of said transmission medium, transmitting it to the receiving end of the latter and feeding it to the transversal equalizer, b. generating at the receiving end a second reference signal sequence identical with the first reference signal sequence, c. deriving a first error signal from a comparison of a first signal of said second reference signal sequence and a corresponding signal of a first output signal sequence produced by said transversal equalizer when fed with said first reference signal sequence, d. adjusting the attenuator settings in response to said error signal and thereby imparting to the error signal at least two different weights for the adjustment of at least two respective numbers of attenuator settings, and e. repeating the steps c) and d) with subsequent signals of the respective signal sequences thus incrementally readjusting the attenuator settings in order that said output signal sequence and said second reference signal sequence at least approximatively converge; and in a second phase: f. transmitting communication signals through the transmission medium and feeding them to the transversal equalizer, g. deriving by threshold detecting third reference signals from a second output signals produced by said transversal equalizer when fed with the communication signals, h. deriving second error signals from a comparison of subsequent second output signals and the corresponding third reference signals, and i. readjusting the attenuator settings in response to said second error signals in order to compensate for alterations of the transmission system.
Claim 2
Independent Claim
283 words
A method for establishing optimum attenuator settings in a transversal equalizer intended for correction of distortion imposed upon pulse-amplitude-modulated communication signals in passage through a transmission medium comprising in a first phase: a. generating a first reference signal sequence at the transmitting end of said transmission medium, transmitting it to the receiving end of the latter and feeding it to the transversal equalizer, b. generating at the receiving end a second reference signal sequence identical with the first reference signal sequence, c. deriving a first error signal from a comparison of a first signal of said second reference signal sequence and a corresponding signal of a first output signal sequence produced by said transversal equalizer when fed with said first reference signal sequence, d. adjusting the attenuator settings in response to said error signal and thereby imparting to the error signal at least two different weights for the adjustment of at least two respective numbers of attenuator settings, and e. repeating the steps c) and d) with subsequent signals of the respective signal sequences thus incrementally readjusting the attenuator settings in order that said output signal sequence and said second reference signal sequence at least approximatively converge; and in a second phase: f. transmitting communication signals through the transmission medium and feeding them to the transversal equalizer, g. deriving by threshold detecting third reference signals from a second output signals produced by said transversal equalizer when fed with the communication signals, h. deriving second error signals from a comparison of subsequent second output signals and the corresponding third reference signals, and i. readjusting the attenuator settings in response to said second error signals in order to compensate for alterations of the transmission system.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein the step i) is performed according to step d).
Claim 4
Dependent Claim
68 words
The method of claim 1 wherein the attenuator settings are adjusted by groups, the attenuator settings of each group relating to adjacent storage places along a delay line contained in said transversal equalizer, and wherein the error signal is imparted a weight for the adjustment of the group relating to the middle storage places which is larger than the weight imparted for the adjustment of the other groups.
Claim 5
Dependent Claim
33 words
The method of claim 3 wherein the weights decrease monotonicly from their maximum value for the middle group and wherein the weights for the adjustment of adjacent groups differ by the factor 2.
Claim 6
Dependent Claim
33 words
The method of claim 1 wherein reference signals and communication signals are sampled and fed in sampled form to the transversal equalizer and wherein the attenuator settings are readjusted for each sample value.
Claim 7
Independent Claim
365 words
A method for establishing optimum attenuator settings in a transversal equalizer intended for correction of distortion imposed upon pulse-amplitude-modulated communication signals in passage through a transmission medium, wherein in the equalizer there is generated from each input signal a number of delayed signals, each such signal is attenuated by an attenuator and the thus attenuated signals are summed to produce the corresponding equalizer output signal, the method comprising in a first phase: a. generating a first signal sequence at the transmission end of said transmission, transmitting it to the receiving end and feeding it to said transversal equalizer, b. generating at the receiving end a second reference signal sequence identical with the first reference signal sequence, c. deriving a first error signal from a comparison of a first signal of said second reference signal sequence and a corresponding signal of a first output signal sequence produced by said transversal equalizer when fed with said first reference signal sequence, d. calculating correction values for the attenuator settings by multiplying the instantaneous values of respective delayed signals with said error signal and with a respective weighting factor from 0 to 1, whereby for the calculation of at least one number of correction values there is used a larger weighting factor than for the calculation of the other correction values, e. adjusting the attenuator settings of the transversal equalizer by adding the thus calculated correction values to the corresponding instantaneous attenuator settings, and f. iteratively repeating steps c) - e) with subsequent signals of said second reference signal sequence and said first output signal sequence in order that said first output signal sequence and said second reference signal sequence at least approximatively converge; and in a second phase: g. transmitting communication signals through the transmission medium and feeding them to the transversal equalizer, h. deriving by threshold detecting third reference signals from second output signals produced by the transversal equalizer when fed with said communication signals, i. deriving second error signals from a comparison of subsequent second output signals and the corresponding third reference signals, and j. readjusting the attenuator settings in response to said second error signals in order to compensate for alternations of the transmission medium.
Claim 8
Independent Claim
365 words
A method for establishing optimum attenuator settings in a transversal equalizer intended for correction of distortion imposed upon pulse-amplitude-modulated communication signals in passage through a transmission medium, wherein in the equalizer there is generated from each input signal a number of delayed signals, each such signal is attenuated by an attenuator and the thus attenuated signals are summed to produce the corresponding equalizer output signal, the method comprising in a first phase: a. generating a first signal sequence at the transmission end of said transmission, transmitting it to the receiving end and feeding it to said transversal equalizer, b. generating at the receiving end a second reference signal sequence identical with the first reference signal sequence, c. deriving a first error signal from a comparison of a first signal of said second reference signal sequence and a corresponding signal of a first output signal sequence produced by said transversal equalizer when fed with said first reference signal sequence, d. calculating correction values for the attenuator settings by multiplying the instantaneous values of respective delayed signals with said error signal and with a respective weighting factor from 0 to 1, whereby for the calculation of at least one number of correction values there is used a larger weighting factor than for the calculation of the other correction values, e. adjusting the attenuator settings of the transversal equalizer by adding the thus calculated correction values to the corresponding instantaneous attenuator settings, and f. iteratively repeating steps c) - e) with subsequent signals of said second reference signal sequence and said first output signal sequence in order that said first output signal sequence and said second reference signal sequence at least approximatively converge; and in a second phase: g. transmitting communication signals through the transmission medium and feeding them to the transversal equalizer, h. deriving by threshold detecting third reference signals from second output signals produced by the transversal equalizer when fed with said communication signals, i. deriving second error signals from a comparison of subsequent second output signals and the corresponding third reference signals, and j. readjusting the attenuator settings in response to said second error signals in order to compensate for alternations of the transmission medium.
Claim 9
Dependent Claim
17 words
The method of claim 6 wherein the step j) is performed according to steps d) and e).
Claim 10
Dependent Claim
165 words
Apparatus for correction of distortion imposed upon pulse-amplitude-modulated communication signals in passage trough a transmission medium comprising a transversal equalizer at the receiving end of said transmission medium receiving transmitted signals, the attenuator settings of said equalizer being adjustable, means connectable to said equalizer generating a second reference signal sequence, threshold means generating a third reference signal sequence from output signals of said equalizer, comparing means deriving error signals from a comparison of subsequent output signals of said equalizer and corresponding signals of said second or third reference signal sequence, respectively, means responsive to said error signals incrementally adjusting said attenuator settings in response to said error signals, said adjusting means including an attenuating means imparting to said error signal at least two different weights for the adjustment of at least two respective numbers of attenuator settings, and switching means connecting in accordance with a given programme said comparing means to either the means generating the second reference signal sequence or to the threshold means.
Claim 11
Dependent Claim
165 words
Apparatus for correction of distortion imposed upon pulse-amplitude-modulated communication signals in passage trough a transmission medium comprising a transversal equalizer at the receiving end of said transmission medium receiving transmitted signals, the attenuator settings of said equalizer being adjustable, means connectable to said equalizer generating a second reference signal sequence, threshold means generating a third reference signal sequence from output signals of said equalizer, comparing means deriving error signals from a comparison of subsequent output signals of said equalizer and corresponding signals of said second or third reference signal sequence, respectively, means responsive to said error signals incrementally adjusting said attenuator settings in response to said error signals, said adjusting means including an attenuating means imparting to said error signal at least two different weights for the adjustment of at least two respective numbers of attenuator settings, and switching means connecting in accordance with a given programme said comparing means to either the means generating the second reference signal sequence or to the threshold means.
Claim 12
Dependent Claim
111 words
The apparatus of claim 8 wherein the transversal equalizer comprises a delay line including a number of storage places and a respective attenuator connected with each storage place, wherein the adjusting means responsive to said error signals comprises for each attenuator within the transversal equalizer a separate adjusting circuit including a multiplier and an accumulator, and wherein the attenuating means including in the adjusting means consists of at least two attenuating multipliers, the multipliers of the adjusting circuits being connected in parallel by groups with one of their inputs and each group of multipliers being connected by their common inputs to the output of a respective one of said attenuating multipliers.
Claim 13
Dependent Claim
41 words
The apparatus of claim 8 further comprising a sampling device connected in series with the input of said equalizer and wherein the adjusting means responsive to the error signals is adapted to sequentially readjust the attenuator settings after each sampling step.
Claim 14
Dependent Claim
30 words
The apparatus of claim 10 further comprising a analog-to-digital converter connected in series with the equalizer input, and wherein the equalizer and all related means are adapted to work digitally.
Claim 15
Dependent Claim
237 words
The apparatus of claim 10 wherein the transversal equalizer and the adjusting means responsive to said error signals comprise a first shift register back-coupled via a first switch means for storing a number of sample values from said sampling device, a second shift register back-coupled via an adder for storing a corresponding number of attenuator settings, a controllable attenuator for attenuating error signals from said comparing means, a multiplier having its inputs connected via second switch means to said shift register and to said controllable attenuator, and having its output connected via third switch means to said adder and to a product accumulator connected to said comparing means, and a control device controlling said switch means, said shift register and said controllable attenuator so that for each sample value fed into the first shift register first all the sample values stored within the latter are sequentially multiplied by the corresponding attenuator settings stored within the second shift register by means of said multiplier, the thus obtained products are summed up by the product accumulator and fed to said comparing means which generates a corresponding error signal, and then the sample values are sequentially multiplied by individually attenuated error signals, whereby the degree of attenuation of the controllable attenuator is controlled according to a given programme contained in the control device, and the thus obtained products are fed to said adder and added to their corresponding attenuator settings.
Claim 16
Dependent Claim
259 words
The apparatus of claim 10 wherein the transversal equalizer and the adjusting means responsive to said error signals comprise a first shift register back-compled via a first switch means for storing a number of sample values from said sampling device, a second shift register back-coupled via an adder for storing a corresponding number of attenuator settings, a controllable attenuator for attenuating the sample values from said first shift register, a multiplier having a input connected via second switch means and said controllable attenuator to said first shift register, two other inputs being connected via third and forth switch means to said shift register and said comparing means, and the output being connect via fifth switch means to said adder and to a product accumulator connected to said comparing means, and a control device controlling said switch means, said shift register and said controllable attenuator so that for each sample value fed into the first shift register first all the sample values stored within the latter are sequentially multiplied by the corresponding attenuator settings stored within the second shift register by means of said multiplier, the thus obtained products are summed up by the product accumulator and fed to said comparing means which generates a corresponding error signal, and then the sample values are individually attenuated by said controllable attenuator in accordance with a given programme contained in the control device, the thus attenuated sample values are sequentially multiplied by said error signals, and the thus obtained products are fed to said adder and added to their corresponding attenuator settings.
Claim 17
Dependent Claim
262 words
The apparatus of claim 10 wherein the transversal equalizer and the adjusting means responsive to said error signals comprise a first shift register back-coupled via a first switch means for storing a number of sample values from said sampling device, a second shift regster back-coupled via an adder for storing a corresponding number of attenuator settings, a multiplier having its inputs connected via second switch means to said first and second shift registers and said comparing means, a product accumulator connected via a third switch means to the output of said multiplier and further connected to said comparing means. a controllable attenuator connected by its input via a forth switch means to the output of said multiplier and by its output to said adder, and a control device controlling said switch means, said shift registers and said controllable attenuator so that for each sample value fed into the first shift register first all the sample values stored within the latter are sequentially multiplied by the corresponding attenuator settings stored within the second shift register by means of said multiplier, the thus obtained products are summed up by the product accumulator and fed to said comparing means which generates a corresponding error signal, and then the sample values are sequentially multiplied by the error signal and the thus obtained products are individually attenuated by said controllable attenuator whereby the attenuating degrees of the latter are controlled in accordance with a given programme within said control device, and the thus attenuated products are fed to the adder and added to their corresponding attenuator settings.
Claim 18
Dependent Claim
13 words
The apparatus of claim 10 wherein the attenuating means is a shift register.
References Cited (Backward Citations)
US3614622A
Cited
US3697897A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-18 | 1981-01-17 | 1981-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-18 | 1985-01-17 | 1985-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-18 | 1989-01-17 | 1989-07-19 | $7700.00 | Window Closed / Lapsed |