US3875333A
Expired / Lapsed
US
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Method of eliminating errors of discrimination due to intersymbol interference and a device for using the method
Assignee: Hitachi Ltd
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Filing: 1972-10-06
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Granted: 1975-04-01
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Expires: 1992-10-06
Abstract
Abstract A method of eliminating errors of discrimination due to intersymbol interference by discriminating an input signal with respect to a first predetermined threshold value thereby to produce a train of pulses in accordance with the results of the discrimination, digitally delaying the train of pulses, producing a first analog signal which is similar to the input signal from the train of pulses, analogically delaying the input signal, comparing the analogically delayed input signal with the first analog signal to produce a difference signal with respect to a second predetermined threshold value to produce a pulse signal in accordance with the result of the last-mentioned discrimination, and digitally adding or half adding the pulse signal to the digitally delayed train of pulses to provide a corrected train of pulses thereby reducing the rate of errors of discrimination due to intersymbol interference. The method also includes the producing of a second analog signal from the pulse signal obtained by the last-mentioned discrimination, analogically delaying the difference signal, and comparing the analogically delayed difference signal with the second analog signal to provide an output signal indicative of the discrimination error rate, and a device for using the method.
Inventors
- 👤 Toshio Nakano
- 👤 Yasushi Kudo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:15
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
176 words
A method of eliminating error of discrimination due to intersymbol interference comprising steps of primarily discriminating an input signal to provide a discriminated pulse train, digitally delaying said discriminated pulse train by means of a shift register comprising at least two flip-flops, weighting an output or NOT output of each of said flip-flops, analogically adding said weighted signals to each other, analogically delaying said input signal, comparing the output produced in said step of analogical delay with the output produced in said step of analogical addition, secondarily discriminating the result of said comparison by reference to a threshold value, generating a pulse corresponding to the result of said secondary discrimination, digitally half-adding said pulse to the output of said shift register, shaping said pulse corresponding to the result of said secondary discrimination into a waveform corresponding to the waveform of the input signal, analogically delaying the output produced in said step of comparison, and comparing said pulse of the corresponding waveform with said analogically delayed signal derived from said signal produced in said step of comparison.
Claim 2
Independent Claim
176 words
A method of eliminating error of discrimination due to intersymbol interference comprising steps of primarily discriminating an input signal to provide a discriminated pulse train, digitally delaying said discriminated pulse train by means of a shift register comprising at least two flip-flops, weighting an output or NOT output of each of said flip-flops, analogically adding said weighted signals to each other, analogically delaying said input signal, comparing the output produced in said step of analogical delay with the output produced in said step of analogical addition, secondarily discriminating the result of said comparison by reference to a threshold value, generating a pulse corresponding to the result of said secondary discrimination, digitally half-adding said pulse to the output of said shift register, shaping said pulse corresponding to the result of said secondary discrimination into a waveform corresponding to the waveform of the input signal, analogically delaying the output produced in said step of comparison, and comparing said pulse of the corresponding waveform with said analogically delayed signal derived from said signal produced in said step of comparison.
Claim 3
Independent Claim
160 words
A device for eliminating errors of discrimination due to intersymbol interference comprising means for discriminating input signals, means for digitally delaying a train of pulses obtained by said discriminating means, means for analogically delaying said input signals, means for changing to a predetermined level the amplitude of each pulse of said pulse train, means for comparing said analogically delayed input signals with said signal having the predetermined amplitude, means for discriminating the output of said comparing means with reference to a predetermined threshold value, means for generating a pulse corresponding to the output of said discriminating means, means for digitally half-adding said pulse to the output of said digitally delaying means, means for shaping the pulse generated by said last-mentioned discriminating means into a waveform corresponding to the waveform of the input signals, means for analogically delaying the output signal of said comparator means, and means for comparing said signal of the corresponding waveform with said analogically delayed output signal.
Claim 4
Independent Claim
160 words
A device for eliminating errors of discrimination due to intersymbol interference comprising means for discriminating input signals, means for digitally delaying a train of pulses obtained by said discriminating means, means for analogically delaying said input signals, means for changing to a predetermined level the amplitude of each pulse of said pulse train, means for comparing said analogically delayed input signals with said signal having the predetermined amplitude, means for discriminating the output of said comparing means with reference to a predetermined threshold value, means for generating a pulse corresponding to the output of said discriminating means, means for digitally half-adding said pulse to the output of said digitally delaying means, means for shaping the pulse generated by said last-mentioned discriminating means into a waveform corresponding to the waveform of the input signals, means for analogically delaying the output signal of said comparator means, and means for comparing said signal of the corresponding waveform with said analogically delayed output signal.
Claim 5
Independent Claim
158 words
A method of eliminating errors of discrimination due to intersymbol interferencE comprising the steps of first discriminating input signals, digitally delaying a train of pulses obtained by said first discrimination, analogically delaying said input signals, changing to a predetermined level the amplitude of each pulse of said pulse train obtained as the result of said first discrimination of said input signals, comparing said analogically delayed input signals with said signal having said predetermined amplitude, second discriminating the result of said comparison with reference to a predetermined threshold value, generating a pulse corresponding to the result of second discrimination, digitally half-adding said pulse to the output produced in said step of digital delay, analogically delaying the output signal of said comparison, shaping the pulse generated as the result of said second discrimination into a waveform corresponding to the waveform of the input signals, and comparing said signal of the corresponding waveform with said analogically delayed signal of said comparison.
Claim 6
Independent Claim
158 words
A method of eliminating errors of discrimination due to intersymbol interferencE comprising the steps of first discriminating input signals, digitally delaying a train of pulses obtained by said first discrimination, analogically delaying said input signals, changing to a predetermined level the amplitude of each pulse of said pulse train obtained as the result of said first discrimination of said input signals, comparing said analogically delayed input signals with said signal having said predetermined amplitude, second discriminating the result of said comparison with reference to a predetermined threshold value, generating a pulse corresponding to the result of second discrimination, digitally half-adding said pulse to the output produced in said step of digital delay, analogically delaying the output signal of said comparison, shaping the pulse generated as the result of said second discrimination into a waveform corresponding to the waveform of the input signals, and comparing said signal of the corresponding waveform with said analogically delayed signal of said comparison.
Claim 7
Dependent Claim
56 words
A method according to claim 3, wherein the step of changing to a predetermined level the amplitude of each of a train of pulses obtained as the result of first discrimination of input pulses includes applying the input signals to a filter, the filter including at least one of a coil, a capacitor and a resistor.
Claim 8
Dependent Claim
58 words
A method according to claim 3, wherein the step of comparing the analogically delayed input signals with the signal with the predetermined amplitude includes applying said signals to a differential amplifier with mutually complementary output terminals, in which the two outputs of said differential amplifier are full-wave rectified and the rectified output is discriminated by the second discrimination.
Claim 9
Dependent Claim
79 words
A method according to claim 3, in which said step of generating a pulse corresponding to the result of said second discrimination comprises steps of obtaining two outputs from a differential amplifier used for said step of comparing and having two mutually complementary output terminals, discriminating separately with a pair of discriminator means the two outputs of the differential amplifier, generating a pulse corresponding to each output of said discriminator means, and applying said pulse through an OR gate.
Claim 10
Dependent Claim
142 words
A method according to claim 3, in which said step of generating a pulse corresponding to the result of the second discrimination comprises steps of obtaining two outputs from a differential amplifier used for step of comparing and having two mutually complementary output terminals, discriminating separately with a pair of discriminator means the two outputs of the differential amplifier, generating a pulse corresponding to each output of said discriminator means, applying to a first NAND gate the output produced in said step of digital delay and one of the outputs produced in said step of pulse generation, applying to a second NAND gate the other of the outputs produced in said step of pulse generation and a NOT output produced in said step of digital delay, and applying to a third NAND gate the outputs of said first and second NAND gates.
Claim 11
Independent Claim
123 words
A method of eliminating errors of discrimination due to intersymbol interference comprising the steps of discriminating an input signal with respect to a first predetermined threshold value thereby to produce a train of pulses, analogically delaying said input signal, digitally delaying said train of pulses, producing a first analog signal corresponding to the waveform of said input signal from said train of pulses, comparing said analogically delayed input signal with said first analog signal thereby to produce a difference signal indicative of the difference therebetween, discriminating said difference signal with respect to a second predetermined threshold value thereby to produce a pulse signal, and digitally half-adding said pulse signal to said digitally delayed train of pulses to provide a corrected train of pulses.
Claim 12
Independent Claim
123 words
A method of eliminating errors of discrimination due to intersymbol interference comprising the steps of discriminating an input signal with respect to a first predetermined threshold value thereby to produce a train of pulses, analogically delaying said input signal, digitally delaying said train of pulses, producing a first analog signal corresponding to the waveform of said input signal from said train of pulses, comparing said analogically delayed input signal with said first analog signal thereby to produce a difference signal indicative of the difference therebetween, discriminating said difference signal with respect to a second predetermined threshold value thereby to produce a pulse signal, and digitally half-adding said pulse signal to said digitally delayed train of pulses to provide a corrected train of pulses.
Claim 13
Dependent Claim
33 words
A method according to claim 8, further comprising the step Of counting the number of pulse signals of the last-mentioned discrimination over a predetermined period as an indication of the discrimination error rate.
Claim 14
Dependent Claim
45 words
A method according to claim 8, further comprising the steps of producing a second analog signal from said pulse signal obtained by the last-mentioned discrimination, analogically delaying the analogically delayed input signal, and comparing the twice analogically delayed input signal with the second analog signal.
Claim 15
Dependent Claim
53 words
A method according to claim 8, further comprising the steps of producing a second analog signal from said pulse signal obtained by the lastmentioned discrimination, analogically delaying said difference signal, and comparing said analogically delayed difference signal with said second analog signal to provide an output signal indicative of the discrimination error rate.
Claim 16
Dependent Claim
38 words
A method according to claim 9, wherein the step of producing the first analog signal includes applying the train of pulses to a filter, the filter including at least one of a coil, a capacitor and a resistor.
Claim 17
Dependent Claim
59 words
A method according to claim 11, wherein the step of comparing said analogically delayed input signal with said first analog signal is carried out by applying the signals to a differential amplifier with mutually complementary output terminals, in which the two outputs of said differential amplifier are full-wave rectified and the rectified output is discriminated by the second discriminator.
Claim 18
Dependent Claim
73 words
A method according to claim 11, wherein a second difference signal which is complementary of said first-mentioned difference signal is produced by comparing said analogically delayed signal with said first analog signal, said first and second difference signals being independently subject to respective discriminations with respect to the second predetermined threshold value and then the outputs derived from said respective discriminations are applied to an OR gate thereby to produce said pulse signal.
Claim 19
Dependent Claim
141 words
A method according to claim 11, wherein a second difference signal which is complementary of said first-mentioned difference signal is produced by comparing said analogically delayed signal with said first analog signal, said first and second difference signals being independently subject to respective discriminations with respect to the second predetermined threshold value, one of the outputs derived from said respective discriminations is applied to a first NAND circuit to which the digitally delayed pulse signal is also applied, and the other of said outputs is applied to a second NAND circuit to which a NOT output of said digitally delayed pulse signal is also applied, and the outputs of said first and second NAND circuits are applied to a third NAND circuit thereby to produce a pulse signal representing the result of the discrimination with respect to the second threshold value.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |