US3586965A
Expired / Lapsed
US
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Apparatus for testing and evaluating a magnetic medium for defects
Assignee: General Kinetics Inc
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Filing: 1969-10-13
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Granted: 1971-06-22
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Expires: 1989-10-13
Abstract
Abstract Apparatus for testing and evaluating a magnetic recording medium having a plurality of data tracks thereon wherein the apparatus significantly reduces the number of electronic circuits heretofore required to accomplish the complete testing of such mediums and wherein the apparatus provides two channels. One channel is associated with a reference or clock track while the other channel is associated with the remaining tracks on the medium. A separate transducer head is provided for each of the individual tracks and predetermined pairs of the transducer heads other than the reference transducer heads are connected in electrical parallel and opposing relationship whereby the apparatus indicates the presence of defects in the medium in any one of the tracks without the necessity of supplying a separate channel for each track.
Inventors
- 👤 Dale C Whysong
- 👤 John F Walton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:55
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/12; G01R33/1207
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
178 words
Apparatus for testing and evaluating a magnetic recording medium wherein the medium has a plurality of spaced-apart data tracks with substantially aligned signals thereon, said apparatus comprising: a separate magnetic transducer head adapted to be positioned over each of said tracks for converting said signals to electrical signals, one of said transducer heads being designated as a reference head; predetermined pairs of said transducer heads other than said reference head connected in electrical parallel and opposing relationship; a first channel operatively coupled to said reference head for providing a series of strobe pulses; first gating means for receiving said strobe pulses; a second channel operatively coupled to said pairs of transducer heads for providing pulses to said gating means when defects in any one of said tracks corresponding to said pairs of transducer heads is sensed by one of said transducer head pairs; and means operatively associated with said first and second channels for counting the number of defects occurring in said data tracks which are associated with said transducer head pairs and with said reference transducer head.
Claim 2
Dependent Claim
178 words
Apparatus for testing and evaluating a magnetic recording medium wherein the medium has a plurality of spaced-apart data tracks with substantially aligned signals thereon, said apparatus comprising: a separate magnetic transducer head adapted to be positioned over each of said tracks for converting said signals to electrical signals, one of said transducer heads being designated as a reference head; predetermined pairs of said transducer heads other than said reference head connected in electrical parallel and opposing relationship; a first channel operatively coupled to said reference head for providing a series of strobe pulses; first gating means for receiving said strobe pulses; a second channel operatively coupled to said pairs of transducer heads for providing pulses to said gating means when defects in any one of said tracks corresponding to said pairs of transducer heads is sensed by one of said transducer head pairs; and means operatively associated with said first and second channels for counting the number of defects occurring in said data tracks which are associated with said transducer head pairs and with said reference transducer head.
Claim 3
Dependent Claim
24 words
Apparatus as in claim 1 in combination with means operatively associated with said medium for recording said substantially aligned signals on said data tracks.
Claim 4
Dependent Claim
76 words
Apparatus as in claim 1 wherein said first channel includes first automatic gain control means in circuit with said reference head and wherein said second channel includes second automatic gain control means in circuit with said pairs of transducer heads, said first and second automatic gain control means being in operative relationship with respect to each other to enable said first automatic gain control means to control the operation of said second automatic gain control means.
Claim 5
Dependent Claim
93 words
Apparatus as in claim 3 wherein said first and second channels each further include: potentiometer means coupled to respective ones of said automatic gain control means; full wave detectors adjustably set to provide electrical output pulses when the inputs thereto reach a predetermined value; and amplifier means respectively coupled between each of said potentiometer means and each of said full wave detectors; said potentiometer means each being adjustable to determine at what fraction of the maximum amplitude of the output signal from said amplifier means said full wave detector will produce output pulses.
Claim 6
Dependent Claim
128 words
Apparatus as in claim 4 further including: delay means coupled between the full wave detector of said first channel and said gating meAns for providing said strobe pulses to said gating means at times when the amplitudes of the said signals on said medium are at a maximum as detected by respective ones of said transducer heads whereby the difference in amplitudes of said signals respectively associated with said predetermined pairs of transducer heads as caused by skew of said medium, for example, are at a minimum so that said gating means is not gated on as a result of skew of said medium as opposed to defects in said medium and a false indication of a defect in said medium is not registered in said counter means.
Claim 7
Dependent Claim
166 words
Apparatus as in claim 5 wherein said counter means includes: dropout detector means coupled to said first channel full wave detector for producing output pulses only in the absence of input pulses thereto from said first channel full wave detector whereby an output pulse is produced by said dropout detector means upon the occurrence of a defect in said reference track; OR gating means coupled to the outputs of said dropout detector means and the first gating means for providing an output signal whenever a signal is produced by said dropout detector means representing the occurrence of a defect in said medium on said reference track or whenever a signal is produced by said first gating means representing the occurrence of a defect in said medium on one or more of said other tracks; a counter; and counter driver means coupled between said OR gating means and said counter; said counter registering the occurrence of defects in said medium in any one of said data tracks.
Claim 8
Dependent Claim
30 words
Apparatus as in claim 6 wherein said first gating means is an AND gate having its inputs coupled to said second channel full wave detector and to said delay means.
Claim 9
Dependent Claim
50 words
Apparatus as in claim 7 wherein each of said channels includes a preamplifier, said first channel preamplifier coupled between said reference transducer head and said first channel automatic gain control means and said second channel preamplifier coupled between said pairs of transducer heads and said second channel automatic gain control.
Claim 10
Dependent Claim
23 words
Apparatus as in claim 8 wherein said medium is magnetic tape and wherein said tracks are in substantially parallel relationship with one another.
Claim 11
Dependent Claim
12 words
Apparatus as in claim 8 wherein said amplifier means are feedback amplifiers.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |