Patent US3708766A successfully refreshed from Google Patents.
US3708766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic equalizer and method of operation therefor
Assignee: International Business Machines Corp
•
Filing: 1970-12-31
•
Granted: 1973-01-02
•
Expires: 1990-12-31
Abstract
Abstract An automatic equalizer with extremely fast convergence is disclosed. The weight setting procedure or algorithm is basically an iterative operation which can be conveniently expressed by cascaded equalizers. One form of the apparatus utilized consists of a plurality of equalizer stages which have their tap settings changed after successive iterations (the first iteration adjusts the first equalizer stage, the second iteration adjusts the second equalizer stage and so on) such that after n iterations a given initial distortion D is reduced to at most D2 . The algorithm involved and the method of operating the equalizer is also disclosed.
Inventors
- 👤 R Sha
- 👤 D Tang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:46
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03114; H04L25/03133
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
143 words
A method for equalizing an electrical signal comprising the steps of: applying for n iterations an electrical signal sequence represented by the function 1-A to the input of an equalizer arrangement having a plurality of adjustable tap settings; and, equalizing said signal to provide for n iterations an output signal represented by the function 1-A2 where n 1, 2, 3 . . . , and 1-A Alpha N(0), . . . ., Alpha 1(0), Alpha 0(0) 1, Alpha 1(0) , . . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, Alpha is the amplitude value of a signal at a sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 2
Independent Claim
143 words
A method for equalizing an electrical signal comprising the steps of: applying for n iterations an electrical signal sequence represented by the function 1-A to the input of an equalizer arrangement having a plurality of adjustable tap settings; and, equalizing said signal to provide for n iterations an output signal represented by the function 1-A2 where n 1, 2, 3 . . . , and 1-A Alpha N(0), . . . ., Alpha 1(0), Alpha 0(0) 1, Alpha 1(0) , . . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, Alpha is the amplitude value of a signal at a sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 3
Dependent Claim
35 words
A method according to claim 1 further including the step of applying said electrical signal to a signal averaging circuit to generate an output signal which is the average of a number of input signals.
Claim 4
Dependent Claim
33 words
A method according to claim 1 further including the step of: normalizing the function 1-A at the beginning of each iteration to normalize the main pulse of the electrical signal sequence to unity.
Claim 5
Dependent Claim
45 words
A method according to claim 1 wherein the step of equalizing said signal includes the step of: adjusting initially said plurality of tap settings to zero with the exception of the tap settings which correspond to said main pulse, the latter being adjusted to unity.
Claim 6
Dependent Claim
74 words
A method according to claim 4 wherein the step of equalizing said signal includes the steps of: passing said electrical signal for the mth iteration through n equalizer stages, modifying said electrical signal in a summing circuit to provide the function 1+A2 , feeding back said last mentioned function to a tap adjusting means, and modifying the tap settings of the first equalizer stage in accordance with the function 1+A2 where m + n-1.
Claim 7
Dependent Claim
69 words
A method according to claim 5 further including the steps of: passing said electrical signal for n iterations through n equalizer stages, modifying said signal in a summing circuit to provide the function 1+A2 , feeding said last mentioned function to a tap adjusting means and, modifying the tap settings of the n+1th equalizer stage in accordance with the function 1+A2 where n 1, 2, 3 . . .
Claim 8
Independent Claim
169 words
A method for equalizing an electrical signal represented by the function 1-A comprising the steps of: applying said electrical signal for n iterations to the input of a plurality of cascaded equalizer stages each of which have adjustable tap settings the output of one stage being connected to the input of a succeeding stage; and, modifying said electrical signal in each of said equalizer stages to produce successive outputs at the nth of said equalizer stages for successive iterations as represented by the function 1-A2 where n 1, 2, 3. . . , 1-A Alpha N(0), . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, Alpha is the amplitude value of a signal at the sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 9
Independent Claim
169 words
A method for equalizing an electrical signal represented by the function 1-A comprising the steps of: applying said electrical signal for n iterations to the input of a plurality of cascaded equalizer stages each of which have adjustable tap settings the output of one stage being connected to the input of a succeeding stage; and, modifying said electrical signal in each of said equalizer stages to produce successive outputs at the nth of said equalizer stages for successive iterations as represented by the function 1-A2 where n 1, 2, 3. . . , 1-A Alpha N(0), . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, Alpha is the amplitude value of a signal at the sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 10
Dependent Claim
38 words
A method according to claim 7 wherein the step of modifying said electrical signal includes the step of: adjusting said tap settings of the nth of said equalizer stages in accordance with the function 1+A2 where m n-1.
Claim 11
Independent Claim
189 words
A method for equalizing an electrical signal sequence represented by the function 1-A comprising the steps of: applying said electrical signal for n iterations to the input of a plurality of cascaded equalizer stages each of which have adjustable tap settings the output of one stage being connected to the input of a succeeding stage; and, modifying said electrical signal by adjusting said tap settings of the nth of said equalizer stages in accordance with values as represented by the function 1+A2 to produce successive outputs at each of said equalizer stages for successive iterations as represented by the function 1-A2 where 1-A Alpha 118 N(0), . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, n 1, 2, 3 . . . , m n-1, Alpha is the amplitude value of a signal at the sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 12
Independent Claim
189 words
A method for equalizing an electrical signal sequence represented by the function 1-A comprising the steps of: applying said electrical signal for n iterations to the input of a plurality of cascaded equalizer stages each of which have adjustable tap settings the output of one stage being connected to the input of a succeeding stage; and, modifying said electrical signal by adjusting said tap settings of the nth of said equalizer stages in accordance with values as represented by the function 1+A2 to produce successive outputs at each of said equalizer stages for successive iterations as represented by the function 1-A2 where 1-A Alpha 118 N(0), . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, n 1, 2, 3 . . . , m n-1, Alpha is the amplitude value of a signal at the sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 13
Dependent Claim
35 words
A method according to claim 9 further including the step of: normalizing the function 1-A at the beginning of n of each iteration to normalize the main pulse of said electrical signal sequence to unity.
Claim 14
Dependent Claim
80 words
A method according to claim 9 wherein the step of modifying said electrical signal includes the step of: applying said output signal after each iteration to a summing circuit to change said signal to a signal represented by the function 1+A2 , determining the value of the last mentioned function for each sampling point of said electrical signal sequence and, adjusting said adjustable tap settings on the n+1th of said plurality of equalizer stages according to the value previously determined.
Claim 15
Dependent Claim
45 words
A method according to claim 11 further including the step of: adjusting initially the tap settings of said plurality of equalizer stages to zero with the exception of tap settings which correspond to the main pulse of said sequence the latter being adjusted to unity.
Claim 16
Dependent Claim
163 words
Apparatus for equalizing an electrical signal comprising: a signal source for producing an electrical signal a communications medium connecteD to said signal source which introduces distortion on said electrical signal to provide a distorted electrical signal represented by the function 1-A, and means connected to said communications medium for equalizing said distorted electrical signal to provide at the output of said equalizing means an output signal represented by the function 1-A2 for n iterations where n 1, 2, 3 . . . , and 1-A Alpha N(0), . . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, Alpha is the amplitude value of said distorted signal at a sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 17
Dependent Claim
163 words
Apparatus for equalizing an electrical signal comprising: a signal source for producing an electrical signal a communications medium connecteD to said signal source which introduces distortion on said electrical signal to provide a distorted electrical signal represented by the function 1-A, and means connected to said communications medium for equalizing said distorted electrical signal to provide at the output of said equalizing means an output signal represented by the function 1-A2 for n iterations where n 1, 2, 3 . . . , and 1-A Alpha N(0), . . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, Alpha is the amplitude value of said distorted signal at a sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 18
Dependent Claim
38 words
Apparatus according to claim 13 further including means interposed between said communications medium and said equalizing means for averaging said distorted electrical signal to generate an output signal which is the average of a plurality of input signals.
Claim 19
Dependent Claim
90 words
Apparatus according to claim 13 wherein said means for equalizing said distorted electrical signal includes a plurality of equalizer stages each having a plurality of adjustable tap settings, the output of one stage being connected to the input of a succeeding stage, means connected to the last of said equalizer stages for modifying said output signal to provide the function 1+A2 and, means connected to said modifying means and said adjustable tap settings for adjusting the tap settings associated with n+1th equalizer stage in accordance with said last mentioned function.
Claim 20
Dependent Claim
25 words
Apparatus according to claim 15 wherein said means for modifying said output signal includes a summer circuit which converts the function 1-A2 to 1+A2 .
Claim 21
Dependent Claim
30 words
Apparatus according to claim 15 wherein said means for adjusting includes drive means connected to said adjustable tap settings responsive to the signal sequence represented by the function 1+A2 .
Claim 22
Dependent Claim
15 words
Apparatus according to claim 15 wherein each said equalizer stage includes a tapped delay line.
Claim 23
Dependent Claim
14 words
Apparatus according to claim 15 wherein each said equalizer stage includes a shift register.
Claim 24
Dependent Claim
34 words
Apparatus according to claim 15 further including means connected to said modifying means for adjusting the tap settings of the first of said equalizer stages in accordance with the function 1+A2 where m n-1.
Claim 25
Dependent Claim
184 words
Apparatus for equalizing an electrical signal represented by the function 1-A comprising: means for applying said electrical signal for n iterations to the input of a plurality of cascaded equalizer stages each of which have a plurality of adjustable tap settings the output of one stage being connected to the input of a succeeding stage; and means connected to the last of said plurality of equalizers and said plurality of adjustable tap settings for modifying said tap settings to produce successive outputs at the nth of said equalizer stage for successive iterations as represented by the function 1-A2 where n 1, 2, 3 . . . , and 1-A Alpha N(0), . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, Alpha is the amplitude value of a signal at a sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 26
Dependent Claim
184 words
Apparatus for equalizing an electrical signal represented by the function 1-A comprising: means for applying said electrical signal for n iterations to the input of a plurality of cascaded equalizer stages each of which have a plurality of adjustable tap settings the output of one stage being connected to the input of a succeeding stage; and means connected to the last of said plurality of equalizers and said plurality of adjustable tap settings for modifying said tap settings to produce successive outputs at the nth of said equalizer stage for successive iterations as represented by the function 1-A2 where n 1, 2, 3 . . . , and 1-A Alpha N(0), . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, Alpha is the amplitude value of a signal at a sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 27
Dependent Claim
22 words
Apparatus according to claim 21 wherein said means for modifying includes a summer circuit which converts the functiOn 1-A2 to 1+A2 .
Claim 28
Dependent Claim
48 words
Apparatus according to claim 22 further including tap adjusting means connected to said summer and each of said equalizer stages for converting the output electrical signal of said summer circuit to mechanical motion and linkages connected between said tap adjusting means and said plurality of adjustable tap settings.
Claim 29
Dependent Claim
182 words
Apparatus for equalizing an electrical signal sequence represented by the function 1-A comprising: means for applying said electrical signal for n iterations to the input of n cascaded equalizer stages each of which have a plurality of adjustable tap settings the output of one stage being connected to the input of a succeeding stage; and means for modifying said electrical signal sequence by adjusting said tap settings of successive stages in accordance with the function 1+A2 to produce an output at the nth equalizer stage for successive iterations as represented by the function 1-A2 where n 1, 2, 3 . . . , 1-A Alpha N(0), . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, m n-1, Alpha is the amplitude value of a signal at a sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 30
Dependent Claim
182 words
Apparatus for equalizing an electrical signal sequence represented by the function 1-A comprising: means for applying said electrical signal for n iterations to the input of n cascaded equalizer stages each of which have a plurality of adjustable tap settings the output of one stage being connected to the input of a succeeding stage; and means for modifying said electrical signal sequence by adjusting said tap settings of successive stages in accordance with the function 1+A2 to produce an output at the nth equalizer stage for successive iterations as represented by the function 1-A2 where n 1, 2, 3 . . . , 1-A Alpha N(0), . . . , Alpha 1(0), Alpha 0(0) 1, Alpha 1(0), . . . . , Alpha N(0) and is the output of a transmission medium in response to a unit pulse input decomposed as the main pulse and side lobes, m n-1, Alpha is the amplitude value of a signal at a sampling instant and the subscripts associated with the term Alpha are the numbers of the sampling instants before and after the main pulse.
Claim 31
Dependent Claim
83 words
Apparatus according to claim 24 wherein said means for modifying includes a summing circuit connected to the last of said plurality of equalizer stages to change said signal to a signal represented by the function 1+A2 , means connected to said summer circuit for determining the value of said last mentioned function for a plurality of sampling points of said electrical signal sequence, and means for adjusting each of said plurality of tap settings on the n+1th of said plurality of equalizer stages.
Claim 32
Dependent Claim
38 words
Apparatus according to claim 24 further including, means connected to the first of said plurality of equalizer stages for averaging said electrical signal to generate an output signal which is the average of a plurality of input signals.
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) | 1976-01-02 | 1976-07-03 | 1977-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-02 | 1980-07-03 | 1981-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-02 | 1984-07-03 | 1985-01-02 | $7700.00 | Window Closed / Lapsed |