Patent US3668665A successfully refreshed from Google Patents.
US3668665A
Expired / Lapsed
US
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Apparatus for ensuring timing track accuracy
Assignee: Unisys Corp
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Filing: 1970-04-30
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Granted: 1972-06-06
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Expires: 1990-04-30
Abstract
Abstract A method and apparatus for precisely checking the accuracy of the placing of timing track marks or bits on the periphery of a rotating recording member, such as a magnetic disc or drum, where the spaces between all the timing track marks or bits must be exactly equal and the variations in spacing, if any, cannot be electronically measured. The timing track bits or marks are written during one revolution of the disc or drum and then read back and used as one input to a comparator. The timing track is erased and then the timing track bits are written during two successive resolutions of the disc or drum and read back as the other input to the comparator. If the amplitudes of the two inputs to the comparator are equal then the writing during the second of the two successive revolutions was directly on top of the writing during the first of the two successive revolutions and all the bit spaces are equal.
Inventors
- 👤 Robert J Reynolds
- 👤 Virgilio J Quiogue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:46
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/16
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
42 words
Apparatus for checking the recording of a timing track on a rotating recording member comprising: means for recording timing signals on said track, and means for comparing the amplitude of single-rotation recorded timing signals and successive-rotation recorded timing signals on said track.
Claim 2
Dependent Claim
42 words
Apparatus for checking the recording of a timing track on a rotating recording member comprising: means for recording timing signals on said track, and means for comparing the amplitude of single-rotation recorded timing signals and successive-rotation recorded timing signals on said track.
Claim 3
Dependent Claim
109 words
Apparatus for testing the recording of a timing track on a rotating recording member wherein said timing track has no electronically measurable closure point comprising: means for writing timing track signals during at least one revolution of said member, means for reading said timing track signals and for providing an output signal for at least a portion of said track, the amplitude of said output signal being proportional to the strength of said timing track signals, and means for comparing the amplitude of said output signals from one revolution-writing on said member with the amplitude of said output signals from more than one successive revolution writing on said member.
Claim 4
Dependent Claim
109 words
Apparatus for testing the recording of a timing track on a rotating recording member wherein said timing track has no electronically measurable closure point comprising: means for writing timing track signals during at least one revolution of said member, means for reading said timing track signals and for providing an output signal for at least a portion of said track, the amplitude of said output signal being proportional to the strength of said timing track signals, and means for comparing the amplitude of said output signals from one revolution-writing on said member with the amplitude of said output signals from more than one successive revolution writing on said member.
Claim 5
Dependent Claim
49 words
The apparatus of claim 2 wherein said comparing means includes: first storing means for storing output signals from a portion of said one revolution-writing of said member, and second storing means for storing output signals from a portion of said more than one successive revolution writing of said member.
Claim 6
Dependent Claim
20 words
The apparatus of claim 3 wherein each of said storing means stores signals from the same portion of said member.
Claim 7
Dependent Claim
25 words
The apparatus of claim 3 including: means for selectively coupling the output of said reading and providing means to said first and second storing means.
Claim 8
Dependent Claim
17 words
The apparatus of claim 3 wherein said second storing means includes means for attenuating said output signal.
Claim 9
Independent Claim
108 words
A method for testing the equality of spaces between timing track signals on a rotating member comprising the steps of: writing timing track signals at a first frequency during a single complete revolution of said member, reading said timing track for providing a first readback voltage sample of at least a portion of said single revoLution signals, writing timing track signals at said first frequency during a plurality of complete revolutions of said member, reading said timing track for providing a second readback voltage sample of at least a portion of said plurality of revolutions signals, and comparing the amplitudes of said first and second readback voltage samples.
Claim 10
Independent Claim
108 words
A method for testing the equality of spaces between timing track signals on a rotating member comprising the steps of: writing timing track signals at a first frequency during a single complete revolution of said member, reading said timing track for providing a first readback voltage sample of at least a portion of said single revoLution signals, writing timing track signals at said first frequency during a plurality of complete revolutions of said member, reading said timing track for providing a second readback voltage sample of at least a portion of said plurality of revolutions signals, and comparing the amplitudes of said first and second readback voltage samples.
Claim 11
Dependent Claim
44 words
The method of claim 7 including the step of: changing the ratio of said timing-track-writing-frequency to said rotating-member-speed and repeating all the steps of claim 7, if, but only if, the amplitude of said first and second readback voltage samples are not substantially equal.
Claim 12
Dependent Claim
50 words
The method of claim 7 wherein: said step of reading and providing said first readback voltage sample includes the step of storing said first readback voltage sample, and said step of reading and providing said second readback voltage sample includes the step of separately storing said second readback voltage sample.
Claim 13
Dependent Claim
21 words
The method of claim 9 including the step of: attenuating said second readback voltage sample prior to said step of comparing.
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) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |