Patent US3897379A successfully refreshed from Google Patents.
US3897379A
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Time base error correction for recording systems
Assignee: United States Department of the Navy
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Filing: 1974-10-04
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Granted: 1975-07-29
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Expires: 1994-10-04
Abstract
Abstract A deflutter device for FM recording on magnetic tape which corrects for a varying time base error. Zero crossings from the outputs of a reference oscillator and a reference tone on a first tape track are compared by a flip-flop whose output is a pulse having a width corresponding to the time base error. The output pulse enables a binary counter to provide a digital output which is transformed to an analog voltage by a digital to analog converter. Zero crossings from a second tape track containing recorded data are detected and shifted by a delay multivibrator in accordance with the analog voltage thereby correcting for the time base error.
Inventors
- 👤 Francesco Richard E De
- 👤 Bernard Harris
- 👤 David Hoffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:41
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/16; G11B20/22; G11B20/225; H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/93; H04N5/95
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
242 words
A TIME BASE ERROR CORRECTING SYSTEM FOR FM TAPE RECORDERS HAVING A REFERENCE TONE ON A FIRST TAPE TRACK AND DATA SIGNALS ON A SECOND TAPE TRACK COMPRISING, IN COMBINATION: FIRST PULSE GENERARING MEANS ROR PRODUCING A SERIES OF PERIODIC OUTPUT PULSES HAVING A FREQUENCY EQUAL TO THE AVERAGE FREQUENCY VALUE OF SAID REFERENCE TONE, SECOND PULSE GENERATING MEANS ADAPTED TO RECEIVE SAID REFERENCE TONE FOR PRODUCING A SERIES OF OUTPUT PULSES INDICATIVE OF THE ZERO CROSSINGS OF SAID TONE, DELAY MEANS CONNECTED TO RECEIVE SAID SECOND GENERATING MEANS OUTPUT PULSES FOR PRODUCING A TIME DELAYED REPLICA OUTPUT THEREOF, PULSE WIDTH ENCODING MEANS CONNECTED TO RECEIVE SAID FIRST PULSE GENERATING MEANS OUTPUT SIGNALS AND SAID DELAY MEANS OUTPUT FOR PRODUCING AN OUTPUT PULSE HAVE A VARIABLE WIDTH DEPENDENT UPON THE TIME SEPARATION BETWEEN CORRESPONDING ONES OF SAID FIRST PULSE GENERATING MEANS OUTPUT SIGNALS AND SAID DELAY MEANS OUTPUT PULSES, CLOCKING MEANS CONNECTED TO RECEIVE SAID PULSE WIDTH ENCODING MEANS OUTPUT PULSE FOR PRODUCING A SERIES OF PERIODIC CLOCK PULSES FOR THE DURATION OF SAID OUTPUT PULSE, COUNTING MEANS CONNECTED TO RECEIVE SAID FIRST PULSE GENERATING MEANS OUTPUT PULSES AND SAID CLOCK PULSES FOR PRODUCING DIGITAL COUNT INDICATIVE OF THE WIDTH OF SAID PULSE WIDTH ENCODING MEANS OUTPUT PULSE UPON THE RECEIPT OF INDIVIDUAL ONES OF SAID FIRST PULSE GENERATING MEANS OUTPUT SIGNALS, ANALOG TRANSFORMATION MEANS CONNECTED TO RECEIVE SAID DIGITAL COUNT FOR PRODUCING A SMOOTHED ANALOG SIGNAL REPRESENTATION OF SAID DIGITAL COUNT,
Claim 2
Dependent Claim
242 words
A TIME BASE ERROR CORRECTING SYSTEM FOR FM TAPE RECORDERS HAVING A REFERENCE TONE ON A FIRST TAPE TRACK AND DATA SIGNALS ON A SECOND TAPE TRACK COMPRISING, IN COMBINATION: FIRST PULSE GENERARING MEANS ROR PRODUCING A SERIES OF PERIODIC OUTPUT PULSES HAVING A FREQUENCY EQUAL TO THE AVERAGE FREQUENCY VALUE OF SAID REFERENCE TONE, SECOND PULSE GENERATING MEANS ADAPTED TO RECEIVE SAID REFERENCE TONE FOR PRODUCING A SERIES OF OUTPUT PULSES INDICATIVE OF THE ZERO CROSSINGS OF SAID TONE, DELAY MEANS CONNECTED TO RECEIVE SAID SECOND GENERATING MEANS OUTPUT PULSES FOR PRODUCING A TIME DELAYED REPLICA OUTPUT THEREOF, PULSE WIDTH ENCODING MEANS CONNECTED TO RECEIVE SAID FIRST PULSE GENERATING MEANS OUTPUT SIGNALS AND SAID DELAY MEANS OUTPUT FOR PRODUCING AN OUTPUT PULSE HAVE A VARIABLE WIDTH DEPENDENT UPON THE TIME SEPARATION BETWEEN CORRESPONDING ONES OF SAID FIRST PULSE GENERATING MEANS OUTPUT SIGNALS AND SAID DELAY MEANS OUTPUT PULSES, CLOCKING MEANS CONNECTED TO RECEIVE SAID PULSE WIDTH ENCODING MEANS OUTPUT PULSE FOR PRODUCING A SERIES OF PERIODIC CLOCK PULSES FOR THE DURATION OF SAID OUTPUT PULSE, COUNTING MEANS CONNECTED TO RECEIVE SAID FIRST PULSE GENERATING MEANS OUTPUT PULSES AND SAID CLOCK PULSES FOR PRODUCING DIGITAL COUNT INDICATIVE OF THE WIDTH OF SAID PULSE WIDTH ENCODING MEANS OUTPUT PULSE UPON THE RECEIPT OF INDIVIDUAL ONES OF SAID FIRST PULSE GENERATING MEANS OUTPUT SIGNALS, ANALOG TRANSFORMATION MEANS CONNECTED TO RECEIVE SAID DIGITAL COUNT FOR PRODUCING A SMOOTHED ANALOG SIGNAL REPRESENTATION OF SAID DIGITAL COUNT,
Claim 3
Dependent Claim
36 words
A compensating system according to claim 1 wherein said first pulse generating means further comprises: a reference oscillator for producing a sinusoidally varying periodic signal; and a zero crossing detector for producing the periodic output pulses.
Claim 4
Dependent Claim
18 words
A compensating system according to claim 2 wherein said second pulse generating means is a zero crossing detector.
Claim 5
Dependent Claim
16 words
A compensating system according to claim 3 wherein said delay means is an analog delay line.
Claim 6
Dependent Claim
16 words
A compensating system according to claim 3 wherein said delay means is a clocked shift register.
Claim 7
Dependent Claim
15 words
A compensating system according to claim 3 wherein said delay means is a clocked counter.
Claim 8
Dependent Claim
49 words
A compensating system according to claim 3 wherein said pulse width encoding means is a flip-flop having a set input connected to receive said first pulse generating means output signals, a clear input connected to receive said delay means output, and a non-inverting output for producing the output pulse.
Claim 9
Dependent Claim
60 words
A compensating system according to claim 7 wherein said clocking means further comprises: an oscillator for producing the series of periodic clock pulses; and an AND gate having a first input connected to receive said pulse width encoding means output pulse, a second input connected to receive the oscillator clock pulses, and an output for producing the clocking means output.
Claim 10
Dependent Claim
15 words
A compensating system according to claim 8 wherein said counting means is a binary counter.
Claim 11
Dependent Claim
58 words
A compensating system according to claim 9 wherein said analog transformation means further comprises: a digital-to-analog converter connected to receive said counting means digital count for producing an analog output signal representative thereof; and an analog integrator connected to receive the digital-to-analog converter output signal for integrating said converter output signal and for producing the smoothed analog signal.
Claim 12
Dependent Claim
17 words
A compensating system according to claim 10 wherein said variable delay means is a variable delay multivibrator.
Claim 13
Dependent Claim
71 words
A compensating system according to claim 11 wherein said fourth pulse generating means further comprises: a trailing edge detector connected to receive said variable delay multivibrator output and for providing a series of irregularly shaped output pulses indicative of the trailing edges of respective ones of said variable delay multivibrator output pulses; and a single shot connected to receive said irregular pulses for generating the fourth pulse generating means output pulses.
Claim 14
Dependent Claim
39 words
A compensating system according to claim 12 wherein said fifth pulse generating means is a flip-flop having a toggle input connected to receive said fourth generating means output pulses and a non-inverting output for producing the corrected data signals.
References Cited (Backward Citations)
US3789379A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-28 | 1979-01-27 | 1979-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-28 | 1983-01-27 | 1983-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-28 | 1987-01-27 | 1987-07-29 | $7700.00 | Window Closed / Lapsed |