US3581297A
Expired / Lapsed
US
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Binary data handling system
Assignee: Unisys Corp
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Filing: 1967-09-18
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Granted: 1971-05-25
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Expires: 1987-09-18
Abstract
Abstract A system for reading binary data recorded on a storage medium as magnetic tape in either of several coding techniques. Specifically, the system is capable of reading either phase encoded data or data recorded in the form of nonreturn-to-zero pulses in which one binary value is represented by a flux reversal in a bit cell and the other binary value is represented by the absence of a flux reversal in a bit cell (hereafter called modified NRZ). A positive threshold detector, a negative threshold detector, and a bipolar peak detector are utilized for recovering the NRZ data and part of the preamble of the phase encoded data. The bipolar peak detector is also employed in the recovery of the phase encoded data itself. To recover the NRZ data and the preamble of the phase encoded data, the output of the positive threshold detector and the bipolar peak detector are combined in one AND circuit and the output of the negative threshold detector and the inverse output of the bipolar peak detector are combined in another AND circuit. To recover the phase encoded data, a signal representing the peak-to-peak amplitude of the read head signal is produced by differentiating it and then separately integrating the two half-cycles of the differential signal. The maximum amplitude of the differentiated signal is limited to suppress noise. The integrated signals are applied to a positive threshold detector and a negative threshold detector, respectively. The output of the positive threshold detector is combined with the output of the bipolar peak detector in one AND circuit and the output of the negative threshold detector is combined with the inverse of the output of the bipolar peak detector in another AND circuit to recover the phase encoded data. To check for errors in the phase encoded data, these outputs are switched and applied to two other AND circuits.
Inventors
- 👤 Michael I Behr
- 👤 Lewis B Coon Jr
- 👤 Charles E Bickel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:00
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10009
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
292 words
A binary data handling system comprising: a magnetic read head for producing a first signal representative of data stored on a magnetic surface; a positive threshold detector for generating a second signal to indicate that the first signal exceeds the threshold level of the positive threshold detector; a negative threshold detector for generating a third signal to indicate that the first signal exceeds the threshold level of the negative threshold detector; peak detecting means for producing an indication of the positive and negative peaks of first signal; means for connecting the read head to the inputs of the positive threshold detector, the negative threshold detector, and the peak detecting means; means responsive to each coincidence of the second signal and the positive peak indication of the peak detecting means for generating a pulse; means responsive to each coincidence of the third signal and the negative peak indication of the peak detecting means for generating a pulse; threshold detecting means responsive to the first signal for generating a first indication that the first signal has exceeded a positive threshold level more positive than the threshold level of the positive threshold detector and for generating a second indication that the first signal has exceeded a negative threshold level more negative than the negative threshold level of the negative threshold detector; an error indicator actuated in response to the coincidence of the second signal, the positive peak indication of the peak detecting means, and the second indication of the threshold detecting means, and actuated in response to the coincidence of the third signal, the negative peak indication of the peak detecting means and the first indication of the threshold detecting means; a utilization circuit; and means for coupling the generated pulses to the utilization circuit.
Claim 2
Dependent Claim
292 words
A binary data handling system comprising: a magnetic read head for producing a first signal representative of data stored on a magnetic surface; a positive threshold detector for generating a second signal to indicate that the first signal exceeds the threshold level of the positive threshold detector; a negative threshold detector for generating a third signal to indicate that the first signal exceeds the threshold level of the negative threshold detector; peak detecting means for producing an indication of the positive and negative peaks of first signal; means for connecting the read head to the inputs of the positive threshold detector, the negative threshold detector, and the peak detecting means; means responsive to each coincidence of the second signal and the positive peak indication of the peak detecting means for generating a pulse; means responsive to each coincidence of the third signal and the negative peak indication of the peak detecting means for generating a pulse; threshold detecting means responsive to the first signal for generating a first indication that the first signal has exceeded a positive threshold level more positive than the threshold level of the positive threshold detector and for generating a second indication that the first signal has exceeded a negative threshold level more negative than the negative threshold level of the negative threshold detector; an error indicator actuated in response to the coincidence of the second signal, the positive peak indication of the peak detecting means, and the second indication of the threshold detecting means, and actuated in response to the coincidence of the third signal, the negative peak indication of the peak detecting means and the first indication of the threshold detecting means; a utilization circuit; and means for coupling the generated pulses to the utilization circuit.
Claim 3
Dependent Claim
34 words
The system of claim 1, in which the bipolar threshold detector is a Schmidt trigger circuit with hysteresis corresponding to the amplitude between the higher positive threshold level and the higher negative threshold level.
Claim 4
Dependent Claim
23 words
The system of claim 1, in which the positive threshold detector and the negative threshold detector are Schmidt trigger circuits with negligible hysteresis.
Claim 5
Dependent Claim
38 words
The data handling system of claim 1, in which the threshold detecting means is a bipolar threshold detector having a single bistable output that assumes one state for the first indication and another state for the second indication.
Claim 6
Dependent Claim
18 words
The data handling system of claim 1, in which the peak detecting means is a bipolar peak detector.
Claim 7
Dependent Claim
254 words
A binary data handling system comprising: a source of binary data; a first circuit for processing modified NRZ data, the first circuit including a positive threshold detector, a negative threshold detector, and a bipolar peak detector whose inputs are connected together, first means responsive to each coincidence of the actuation of the positive threshold detector and the positive peak indication of the peak detector for generating a pulse, and second means responsive to each coincidence of the actuation of the negative threshold detector and a negative peak indication of the peak detector for generating a pulse; a second circuit for processing phase encoded data; a utilization circuit connected to the output of the first circuit and the output of the second circuit; means while the source is producing a signal representative of modifiEd NRZ data for coupling the source to the first circuit such that the signal applied to the utilization circuit represents the conventionally encoded data as processed by the first circuit; means while the source is producing the phase encoded data including its preamble for coupling the source to the first circuit before each occurrence of the preamble; and means while the source is producing phase encoded data for coupling the source to the second circuit including circuitry for operating the first and second means of the first circuit to generate pulses at each peak indication of the peak detector irrespective of the actuation of the positive and negative threshold detectors and means for connecting the second circuit to the utilization device.
Claim 8
Dependent Claim
254 words
A binary data handling system comprising: a source of binary data; a first circuit for processing modified NRZ data, the first circuit including a positive threshold detector, a negative threshold detector, and a bipolar peak detector whose inputs are connected together, first means responsive to each coincidence of the actuation of the positive threshold detector and the positive peak indication of the peak detector for generating a pulse, and second means responsive to each coincidence of the actuation of the negative threshold detector and a negative peak indication of the peak detector for generating a pulse; a second circuit for processing phase encoded data; a utilization circuit connected to the output of the first circuit and the output of the second circuit; means while the source is producing a signal representative of modifiEd NRZ data for coupling the source to the first circuit such that the signal applied to the utilization circuit represents the conventionally encoded data as processed by the first circuit; means while the source is producing the phase encoded data including its preamble for coupling the source to the first circuit before each occurrence of the preamble; and means while the source is producing phase encoded data for coupling the source to the second circuit including circuitry for operating the first and second means of the first circuit to generate pulses at each peak indication of the peak detector irrespective of the actuation of the positive and negative threshold detectors and means for connecting the second circuit to the utilization device.
Claim 9
Dependent Claim
165 words
A binary data handling system comprising: a source of binary data; a first circuit for processing conventionally encoded data; a second circuit for processing phase encoded data; a utilization circuit connected to the output of the first circuit and the output of the second circuit; means while the source is producing a signal representative of conventionally encoded data for coupling the source to the first circuit such that the signal applied to the utilization circuit represents the conventionally encoded data as processed by the first circuit; means while the source is producing the phase encoded data including its preamble for coupling the source to the first circuit before each occurrence of the preamble; and means while the source is producing phase encoded data for coupling the source to the second circuit responsive to the sensing by the first circuit of the existence of the preamble such that the signal applied to the utilization circuit represents the phase encoded data as processed by the second circuit.
Claim 10
Dependent Claim
165 words
A binary data handling system comprising: a source of binary data; a first circuit for processing conventionally encoded data; a second circuit for processing phase encoded data; a utilization circuit connected to the output of the first circuit and the output of the second circuit; means while the source is producing a signal representative of conventionally encoded data for coupling the source to the first circuit such that the signal applied to the utilization circuit represents the conventionally encoded data as processed by the first circuit; means while the source is producing the phase encoded data including its preamble for coupling the source to the first circuit before each occurrence of the preamble; and means while the source is producing phase encoded data for coupling the source to the second circuit responsive to the sensing by the first circuit of the existence of the preamble such that the signal applied to the utilization circuit represents the phase encoded data as processed by the second circuit.
Claim 11
Dependent Claim
35 words
The system of claim 7, in which the means for coupling the source to the second circuit is responsive to the count by the first circuit of a predetermined number of pulses in the preamble.
Claim 12
Dependent Claim
349 words
A binary data handling system comprising: first means for producing a signal representative of binary data; second means coupled to the signal producing means for producing a first level when the data representative signal is below a positive threshold level and producing a second level when the data representative signal is above the positive threshold level; a third means coupled to the signal producing means for producing a first level when the data representative signal is below a negative threshold level and for producing a second level when the data representative signal is above the negative threshold level; fourth means coupled to the signal producing means for producing a transition form a first level to a second level at positive peaks of the data representative signal and for producing a transition form the second level to the first level at negative peaks of the data representative signal; fifth means responsive to the coincidence of the production of the second level by the second means and a transition from the first level to the second level by the fourth means for generating a pulse and the coincidence of the production of the second level by the third means and a transition from the second level to the first level by the fourth means for producing a pulse; sixth means responsive to the signal producing means for generating a first indication that the signal representative of binary data has exceeded a positive threshold level more positive than the threshold level of the second means and for generating a second indication that the signal representative of the binary data has exceeded a negative threshold level more negative than the threshold level of the third means; and an error indicator actuated in response to the coincidence of the first level produced by the second means, the second level produced by the fourth means, and the second indication of the sixth means, and actuated in response to the coincidence of the first level produced by the third means, the first level produced by the fourth means, and the first indication of the sixth means.
Claim 13
Dependent Claim
349 words
A binary data handling system comprising: first means for producing a signal representative of binary data; second means coupled to the signal producing means for producing a first level when the data representative signal is below a positive threshold level and producing a second level when the data representative signal is above the positive threshold level; a third means coupled to the signal producing means for producing a first level when the data representative signal is below a negative threshold level and for producing a second level when the data representative signal is above the negative threshold level; fourth means coupled to the signal producing means for producing a transition form a first level to a second level at positive peaks of the data representative signal and for producing a transition form the second level to the first level at negative peaks of the data representative signal; fifth means responsive to the coincidence of the production of the second level by the second means and a transition from the first level to the second level by the fourth means for generating a pulse and the coincidence of the production of the second level by the third means and a transition from the second level to the first level by the fourth means for producing a pulse; sixth means responsive to the signal producing means for generating a first indication that the signal representative of binary data has exceeded a positive threshold level more positive than the threshold level of the second means and for generating a second indication that the signal representative of the binary data has exceeded a negative threshold level more negative than the threshold level of the third means; and an error indicator actuated in response to the coincidence of the first level produced by the second means, the second level produced by the fourth means, and the second indication of the sixth means, and actuated in response to the coincidence of the first level produced by the third means, the first level produced by the fourth means, and the first indication of the sixth means.
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) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |