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US3571730A
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Self-clocked binary data detection system with noise rejection
Assignee: International Business Machines Corp
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Filing: 1968-07-15
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Granted: 1971-03-23
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Expires: 1988-07-15
Abstract
Abstract A self-clocked binary data detection system employing multiple threshold level detection of the differentiated read-back signal. A first threshold level detector detects the zero crossovers of the differentiated read-back signal which correspond to the peaks of the read-back signal to provide the self-clocking and data information. A second threshold level detector determines when the signal amplitude of the differentiated read-back signal is above a certain threshold level. An error is indicated if the second threshold detector fails to indicate that the signal amplitude has reached the second threshold level within a predetermined time after the first threshold detector provides an output signal. The output signal of the second threshold detector is latched on and is reset by the next subsequent zero crossover detection by the first detector. This enables the predetermined time interval to be relatively large with respect to the period of the wave form, therefor insuring low and high frequency detection compatibility with weak input signals.
Inventors
- 👤 George T Webb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:27
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1403; G11B20/1407; G11B20/1419
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
290 words
A data detection and noise separation system for detecting binary information occurring periodically in an electrical pulse signal wave form and for separating the periodic binary information pulses from noise signal pulses occurring within the wave form between groups of binary information pulses comprising: differentiating means for differentiating the electrical pulse signal to produce a differentiated signal in which the zero crossovers of the differentiated signal correspond to the signal peaks of the electrical pulse signal wave form; first threshold level detection means responsive to the output signal of the differentiating means for detecting the zero crossovers of the differentiated signal and for providing an output signal for each such zero crossover; second threshold level detection means responsive to the output signal of the differentiating means for providing an output signal whenever the differentiated signal exceeds a second predetermined level; delay means responsive to the output signal of the first threshold level detection means for delaying said output signal by a predetermined time interval; noise rejection means responsive to the output signal of said delay means and to the output signal of said second threshold level detection means for providing a signal output when said second threshold level detection means fails to provide an output signal prior to the occurrence of the output signal of said delay means; clock pulse generating means responsive to said first threshold level detection means for generating periodic clock pulses corresponding to said binary data information and aperiodic pulses corresponding to noise pulses; data recognition means responsive to said clock pulses for detecting the binary information of the signal wave form and responsive to the output signal of said noise rejection means for inhibiting the detection of said binary information initiated by said clock pulses.
Claim 2
Dependent Claim
290 words
A data detection and noise separation system for detecting binary information occurring periodically in an electrical pulse signal wave form and for separating the periodic binary information pulses from noise signal pulses occurring within the wave form between groups of binary information pulses comprising: differentiating means for differentiating the electrical pulse signal to produce a differentiated signal in which the zero crossovers of the differentiated signal correspond to the signal peaks of the electrical pulse signal wave form; first threshold level detection means responsive to the output signal of the differentiating means for detecting the zero crossovers of the differentiated signal and for providing an output signal for each such zero crossover; second threshold level detection means responsive to the output signal of the differentiating means for providing an output signal whenever the differentiated signal exceeds a second predetermined level; delay means responsive to the output signal of the first threshold level detection means for delaying said output signal by a predetermined time interval; noise rejection means responsive to the output signal of said delay means and to the output signal of said second threshold level detection means for providing a signal output when said second threshold level detection means fails to provide an output signal prior to the occurrence of the output signal of said delay means; clock pulse generating means responsive to said first threshold level detection means for generating periodic clock pulses corresponding to said binary data information and aperiodic pulses corresponding to noise pulses; data recognition means responsive to said clock pulses for detecting the binary information of the signal wave form and responsive to the output signal of said noise rejection means for inhibiting the detection of said binary information initiated by said clock pulses.
Claim 3
Dependent Claim
35 words
The data detection and noise separation system of claim 1 wherein the second threshold level detection means continues to provide an output signal until said first threshold level detection means detects a subsequent zero crossover.
Claim 4
Dependent Claim
53 words
The data detection and noise separation system of claim 1 wherein said first threshold level detection means comprises two threshold level detection circuits, one of said circuits providing an output signal whenever said differentiated signal goes positive and the other of said circuits providing an output signal whenever said differentiated signal goes negative.
Claim 5
Dependent Claim
82 words
The data detection and noise separation system of claim 3 wherein said second threshold level detection means comprises two threshold level detection devices, one of said devices providing an output signal whenever said differentiated signal exceeds a positive threshold level greater than the threshold level of the positive threshold level detection circuit, the other of said devices providing an output signal whenever said differentiated signal exceeds a negative threshold level greater than the threshold level of the negative threshold level detection circuit.
Claim 6
Dependent Claim
37 words
The data detection and noise separation system of claim 4 wherein said second threshold level detection devices continue to provide an output signal as long as their corresponding first threshold level detection circuit provides an output signal.
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) | 1974-03-22 | 1974-09-21 | 1975-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-22 | 1978-09-21 | 1979-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-22 | 1982-09-21 | 1983-03-23 | $7700.00 | Window Closed / Lapsed |