US3727202A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Application of an automatic pulse width controlled, monostable multivibrator for detecting phase encoded information on magnetic tape
Assignee: Telex Computer Products Inc
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Filing: 1972-01-10
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Granted: 1973-04-10
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Expires: 1992-01-10
Abstract
Abstract This invention describes an apparatus for detecting data transitions in a phase-encoded signal. It comprises a trigger means to generate trigger pulses at each signal transition in the phase-encoded signal, whether phase or data transition. The output of the trigger generator goes to an automatic pulse-widthcontrolled monostable multivibrator which, responsive to the trigger pulses, generates a series of pulses of constant pulse width, which occur at each data transition. This multivibrator circuit is inhibited from operating at phase transitions and so it selects the data transitions and provides uniform pulses, of a selected magnitude of the basic time period. Having selected only the data transitions to create a pulse, there is then derived from the multivibrator output in a ONES'' gate a series of short positive pulses which occur at each of the data transitions which are separated by the basic time period. The output of the ONES'' gate goes to a ONES'' detector, which compares the polarity of the pulses from the ONES'' gate with the polarity of the phase-encoded signal immediately after each data transition. Those transitions which have a positive potential then pass through the ONES'' detector and are indicated as detected logical ones.
Inventors
- 👤 L Fort
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:48
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1403; G11B20/1407; G11B20/1419
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
169 words
In a magnetic tape system for detecting phase-encoded information, including means to transport a magnetic tape bearing phase-encoded information past a read means to convert said information into phase-encoded signals, the improvement comprising: a. means responsive to said phase-encoded signals to generate a trigger pulse at each data and phase transition of said phaseencoded signals; b. means responsive to said trigger pulses to generate a constant pulse-width signal of period equal to the basic timing period of said data transition trigger pulses, and of pulse width range of 51 to 99 percent of the basic timing period, said pulses being generated only at each data transition; c. means responsive to said constant pulse width signal to generate a positive detection pulse at each data transition; and d. means to compare the polarity of said phase-encoded signal immediately after each data transition with the polarity of said detection pulses, and to generate an output signal each time the polarity of said phase-encoded data matches the polarity of said detection pulses.
Claim 2
Dependent Claim
169 words
In a magnetic tape system for detecting phase-encoded information, including means to transport a magnetic tape bearing phase-encoded information past a read means to convert said information into phase-encoded signals, the improvement comprising: a. means responsive to said phase-encoded signals to generate a trigger pulse at each data and phase transition of said phaseencoded signals; b. means responsive to said trigger pulses to generate a constant pulse-width signal of period equal to the basic timing period of said data transition trigger pulses, and of pulse width range of 51 to 99 percent of the basic timing period, said pulses being generated only at each data transition; c. means responsive to said constant pulse width signal to generate a positive detection pulse at each data transition; and d. means to compare the polarity of said phase-encoded signal immediately after each data transition with the polarity of said detection pulses, and to generate an output signal each time the polarity of said phase-encoded data matches the polarity of said detection pulses.
Claim 3
Dependent Claim
106 words
The magnetic tape system as in claim 1 in which said means to generate trigger pulses comprises an exclusive OR gate, one input of which is connected directly to the source of phase-encoded signal, and the second input of which is connected to the source of phase-encoded signal through a signal delay means; whereby at each voltage transition of said phase-encoded signal there will be a delay in the change of signal in one input lead while the other input lead will change immediately, whereby during the delay period two input signals will be of different polarities and said EOR gate will generate a trigger pulse.
Claim 4
Dependent Claim
16 words
The magnetic tape system as in claim 1 in which said delay means comprises an amplifier.
Claim 5
Dependent Claim
74 words
The magnetic tape system as in claim 1 in which said means to generate a constant pulse width signal is a non-triggerable monostable multivibrator with its ''''Q'''' output connected to an integrating circuit, a comparision operational amplifier with its positive input connected to the output of said integrating circuit, its negative input connected to a reference voltage, the output of said operational amplifier connected through a resistor to the timing capacitor of said multivibrator.
Claim 6
Dependent Claim
27 words
The magnetic tape system as in claim 1 in which the pulse width of said pulses is approximately equal to 75 percent of said basic timing period.
Claim 7
Dependent Claim
68 words
The magnetic tape system as in claim 1 in which said means to generate a positive detection pulse comprises a capacitor with a first terminal connected to the ''''Q'''' terminal of said multivibrator, and its second terminal connected to a potentiometer intermediate its first end carrying a positive potential, and its second end at ground potential, said second terminal also connected to the input of an inverting amplifier.
Claim 8
Dependent Claim
44 words
The magnetic tape system as in claim 1 in which said means to compare and to generate comprises an AND gate with its first input connected to the output of said inverting amplifier, and its second input connected to said source of phase-encoded signals.
Claim 9
Dependent Claim
94 words
Apparatus for detecting a phase-encoded signal comprising: a. means to generate trigger pulses at each signal transition in the phase-encoded signal; b. means to eliminate from the series of trigger pulses those due to phase transitions of the phase-encoded signal; c. means for generating data pulses by each of the remaining trigger pulses which correspond in time to data transitions; d. means for comparing said data pulses with said phase-encoded signal after each data transition; and e. means for generating an output signal whenever said data pulses correspond in polarity to the phase-encoded signal.
Claim 10
Dependent Claim
94 words
Apparatus for detecting a phase-encoded signal comprising: a. means to generate trigger pulses at each signal transition in the phase-encoded signal; b. means to eliminate from the series of trigger pulses those due to phase transitions of the phase-encoded signal; c. means for generating data pulses by each of the remaining trigger pulses which correspond in time to data transitions; d. means for comparing said data pulses with said phase-encoded signal after each data transition; and e. means for generating an output signal whenever said data pulses correspond in polarity to the phase-encoded 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) | 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 |