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US3727153A
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Automatic equalizer using recirculation
Assignee: International Business Machines Corp
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Filing: 1971-06-30
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Granted: 1973-04-10
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Expires: 1991-06-30
Abstract
Abstract An automatic equalizer with extremely fast convergence is disclosed. The weight setting procedure or algorithm used is basically an iterative operation which can be conveniently expressed by the function 1+A+A2+ . . . +A2 1 where n 0, 1, 2, 3, . . . , and wherein the function has n+1 terms. The tap setting algorithm results from the modification of an input signal represented by the function 1-A in an equalizer having a plurality of tap settings; subsequently converting the modified function in a summer which adds the values 1 or 2 to the negative of the modified signal; recirculating the resulting function and subjecting it to a further modification in the equalizer, the modification being the same as that initially applied and utilizing the resulting output to adjust the tap settings of an equalizer to modify an input signal represented by the function 1-A during the next succeeding iteration. This procedure is carried out iteratively until the value A which represents the distortion of the signal due to sidelobes is reduced to substantially zero value. The tap setting may be accomplished by totally replacing the previous tap settings with net tap settings or the previous tap setting may be incremented to provide a new tap setting.
Inventors
- 👤 Auliffe G Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:27
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
157 words
A method for equalizing an electrical signal sequence represented by the function 1-A comprising the steps of: applying for n iterations said electrical signal to at least one equalizer having a plurality of adjustable tap settings, and, modifying said signal to adjust said tap settings of said at least one equalizer in accordance with the function 1+A+A2+ . . . +A2 '''' 1 said function having n+ 1 terms to produce at the output of said at least one equalizer for each iteration the product represented by the function 1-A2 where n 1, 2, 3, . . . , and, in terms of z transform, A Alpha NzN+ Alpha N 1zN 1+ . . . Alpha 0+ . . . Alpha N2 N wherein 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 a main pulse.
Claim 2
Independent Claim
157 words
A method for equalizing an electrical signal sequence represented by the function 1-A comprising the steps of: applying for n iterations said electrical signal to at least one equalizer having a plurality of adjustable tap settings, and, modifying said signal to adjust said tap settings of said at least one equalizer in accordance with the function 1+A+A2+ . . . +A2 '''' 1 said function having n+ 1 terms to produce at the output of said at least one equalizer for each iteration the product represented by the function 1-A2 where n 1, 2, 3, . . . , and, in terms of z transform, A Alpha NzN+ Alpha N 1zN 1+ . . . Alpha 0+ . . . Alpha N2 N wherein 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 a main pulse.
Claim 3
Dependent Claim
111 words
A method for equalizing according to claim 1 wherein the step of modifying said signal includes the steps of: applying said signal to said at least one equalizer to obtain at the output thereof a modified signal represented by the function 1-A2 , converting said modified signal in a summing circuit to obtain a signal represented by the converted function 1+A2 , recirculating said converted function through said at least one equalizer to obtain a signal represented by the function 1+A+A2+ . . . +A2 1, and replacing the tap settings utilized during the nth iteration with new tap settings in accordance with a signal represented by said last mentioned function.
Claim 4
Dependent Claim
121 words
A method for equalizing according to claim 1 wherein the step of modifying said signal includes the steps of: applying said signal to said at least one equalizer to obtain at the output thereof a modified signal represented by the function 1-A2 , converting said modified signal in a summing circuit to obtain the converted function 1+A2 , recirculating said converted function through a slave equalizer having a plurality of tap settings to obtain a signal represented by the function 1+A+A2+ . . . +A2 1, and replacing the tap settings of said at least one equalizer and said slave equalizer utilized during the nth iteration with new tap settings in accordance with a signal represented by said last mentioned function.
Claim 5
Dependent Claim
126 words
A method for equalizing according to claim 1 wherein the step of modifying said signal includes the steps of: applying said signal to said at least one equalizer to obtain at the output thereof a modified signal represented by the function 1-A2 , converting said modified signal in a summing circuit to obtain a signal represented by the converted function A2 , recirculating said converted function through said at least one equalizer to obtain a signal represented by the incrementing function A2 +A2 1+A2 2+ . . . +A2 1 said incrementing function having 2n terms, and, incrementing the tap settings utilized during the nth iteration with said incrementing function to provide a new tap setting represented by the function 1+A+A2+ . . . +A2 1.
Claim 6
Dependent Claim
129 words
A method for equalizing according to claim 1 wherein the step of modifying said signal includes the step of: applying said signal to said at least one equalizer to obtain at the output thereof a modified signal represented by the function 1-A2 , converting said modified signal in a summing circuit to obtain a signal represented by the converted function A2 , recirculating said converted function through a slave equalizer having a plurality of tap settings to obtain a signal represented by the incrementing function A2 +A2 1+A2 2+ . . . +A2 1 said function having 2n terms, and, incrementing the tap settings utilized during the nth iteration with said incrementing function to provide a new tap setting represented by the function 1+A+A2+ . . . +A2 1.
Claim 7
Dependent Claim
27 words
A method according to claim 2 wherein the step of converting said modifieD signal includes the step of adding 2 to the negative of said modified signal.
Claim 8
Dependent Claim
27 words
A method according to claim 3 wherein the step of converting said modified signal includes the step of adding 2 to the negative of said modified signal.
Claim 9
Dependent Claim
27 words
A method according to claim 4 wherein the step of converting said modified signal includes the step of adding 1 to the negative of said modified signal.
Claim 10
Dependent Claim
27 words
A method according to claim 5 wherein the step of converting said modified signal includes the step of adding 1 to the negative of said modified signal.
Claim 11
Dependent Claim
162 words
Apparatus for equalizing an electrical signal sequence represented by the function 1-A comprising: input means for applying said electrical signal for n iterations to at least one equalizer having a plurality of tap settings and means connected to said at least one equalizer for modifying said signal to adjust said tap settings of said at least one equalizer in accordance with the function 1+A+A2 . . . +A2 1 said function having n+1 terms to produce at the output of said at least one equalizer for each iteration the product represented by the function 1-A2 when n 1, 2, 3, . . . , and, in terms of z transform, A Alpha N2N Alpha N 1zN 1+ . . . Alpha O+ . . . Alpha N2 N wherein 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 a main pulse.
Claim 12
Dependent Claim
162 words
Apparatus for equalizing an electrical signal sequence represented by the function 1-A comprising: input means for applying said electrical signal for n iterations to at least one equalizer having a plurality of tap settings and means connected to said at least one equalizer for modifying said signal to adjust said tap settings of said at least one equalizer in accordance with the function 1+A+A2 . . . +A2 1 said function having n+1 terms to produce at the output of said at least one equalizer for each iteration the product represented by the function 1-A2 when n 1, 2, 3, . . . , and, in terms of z transform, A Alpha N2N Alpha N 1zN 1+ . . . Alpha O+ . . . Alpha N2 N wherein 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 a main pulse.
Claim 13
Dependent Claim
133 words
Apparatus according to claim 10 wherein said means for modifying includes: first modifying means connected to said at least one equalizer for modifying said electrical signal to provide at the output thereof a modified signal represented by the function 1-A2 , means connected to said output for converting said modified signal to provide a signal represented by the converted function 1+A2 , means for recirculating said converted function through said at least one equalizer connected to said converting means to provide at said equalizer output a signal represented by the function 1+A+A2+ . . . +A2 1, and, means connected to said tap settings and said equalizer output for replacing the tap settings utilized during the nth iteration with new tap settings in accordance with a signal represented by said last mentioned function.
Claim 14
Dependent Claim
128 words
Apparatus according to claim 10 wherein said means for modifying includes: first modifying means connected to said at least one equalizer for modifying said electrical signal to provide at the output thereof a modified signal represented by the function 1-A2 , means connected to said output for converting said modified signal to provide a signal represented by the converted function 1+A2 , second modifying means connected to said converting means for modifying said converted function to provide a signal represented by the function 1+A+A2+A3+ . . . +A2 1, and, means connected to said tap settings and said first and second modifying means for replacing the tap settings utilized during the nth iteration with new tap settings in accordance with a signal represented by said last mentioned function.
Claim 15
Dependent Claim
136 words
Apparatus according to claim 10 wherein said means for modifying includes: first modifying means connected to said at least one equalizer for modifying said electrical signal to provide at the output thereof a modified signal represented by the function 1-A2 , means connected to said output for converting said modified signal to provide a signal represented by the converted function A2 , means for recirculaTing said converted function through said at least one equalizer to obtain a signal represented by the incrementing function A2 +A2 1+A2 2+ . . . +A2 1 said incrementing function having 2n terms, and, means connected to said recirculating means and said first modifying means for incrementing the tap settings utilized during the nth iteration to provide a new tap setting represented by the function 1+A+A2+ . . . +A2 1.
Claim 16
Dependent Claim
139 words
Apparatus according to claim 10 wherein said means for modifying includes: first modifying means connected to said at least one equalizer for modifying said electrical signal to provide at the output thereof a modified signal represented by the function 1-A2 , means connected to said output for converting said modified signal to provide a signal represented by the converted function A2 , second modifying means connected to said converting means for modifying said converted function to provide a signal represented by the incrementing function A2 +A2 1+A2 2+ . . . +A2 1 said incrementing function having 2n terms, and, means connected to said tap settings and said first and second modifying means for incrementing the tap settings utilized during the nth iteration to provide a new tap setting represented by the function 1+A+A2+ . . . +A2 1.
Claim 17
Dependent Claim
26 words
Apparatus according to claim 11 wherein said first modifying means includes a plurality of multipliers the gains of which are adjusted to produce said modified signal.
Claim 18
Dependent Claim
30 words
Apparatus according to claim 11 wherein said means for converting includes a summing amplifier which adds 2 to the negative of the modified signal represented by the function 1-A2 .
Claim 19
Dependent Claim
31 words
Apparatus according to claim 11 wherein said means for recirculating includes a feedback path between the output of said converting means and said input means of said at least one equalizer.
Claim 20
Dependent Claim
47 words
Apparatus according to claim 11 wherein said means for replacing the tap setting includes tap adjusting means connected to said plurality of tap settings and said output of said at least one equalizer responsive to said signal represented by the function 1+A+A2+ . . . +A2 1.
Claim 21
Dependent Claim
26 words
Apparatus according to claim 12 wherein said first modifying means includes a plurality of multipliers the gains of which are adjusted to produce said modified signal.
Claim 22
Dependent Claim
31 words
Apparatus according to claim 12, wherein said means for converting includes a summing amplifier which adds to 2 to the negative of the modified signal represented by the function 1-A2 .
Claim 23
Dependent Claim
39 words
Apparatus according to claim 12, wherein said second modifying means includes a second equalizer identical to said at least one equalizer and a feedback path between the output of said converting means and the input of said second equalizer.
Claim 24
Dependent Claim
46 words
Apparatus according to claim 12, wherein said means for replacing the tap settings includes tap adjusting means connected to said plurality of said tap settings and the output of said second equalizer responsive to said signal represented by the function 1+A+A2+ . . . +A2 1.
Claim 25
Dependent Claim
26 words
Apparatus according to claim 13, wherein said first modifying means includes a plurality of multipliers the gains of which are adjusted to produce said modified signal.
Claim 26
Dependent Claim
30 words
Apparatus according to claim 13 wherein said means for converting includes a summing amplifier which adds 1 to the negative of the modified signal represented by the function 1-A2 .
Claim 27
Dependent Claim
31 words
Apparatus according to claim 13, wherein said means for recirculating inCludes a feedback path between the output of said converting means and said input means of said at least one equalizer.
Claim 28
Dependent Claim
42 words
Apparatus according to claim 13, wherein said means for incrementing the tap settings includes tap adjusting means connected to said plurality of tap settings and said output of said at least one equalizer responsive to said signal represented by said incrementing function.
Claim 29
Dependent Claim
26 words
Apparatus according to claim 14, wherein said first modifying means includes a plurality of multipliers the gains of which are adjusted to produce said modified signal.
Claim 30
Dependent Claim
30 words
Apparatus according to claim 14, wherein said means for converting includes a summing amplifier which adds 1 to the negative of the modified signal represented by the function 1-A2 .
Claim 31
Dependent Claim
39 words
Apparatus according to claim 14, wherein said second modifying means includes a second equalizer identical to said at least one equalizer and a feedback path between the output of said converting means and the input of said second equalizer.
Claim 32
Dependent Claim
40 words
Apparatus according to claim 14, wherein said means for incrementing the tap settings includes tap adjusting means connected to said plurality of tap settings and said output of said second equalizer responsive to said signal represented by said incrementing function.
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) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |