US3629520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Readout and recording method and apparatus
Assignee: United States Department of the Navy
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Filing: 1969-12-11
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Granted: 1971-12-21
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Expires: 1989-12-11
Abstract
Abstract A method and apparatus for nondestructive readout of magnetic images stored on magnetic thin films and for recording magnetic inputs on thin films. A uniaxially anisotropic thin film of magnetic material carrying a recorded magnetic image is transported over a transmission line in the presence of a magnetic tickling field. A radiofrequency oscillator is coupled to the transmission line and the tickling field is made to oscillate at a relatively low frequency. The magnetic image recorded on the passing thin film is then read out by detecting the modulation of the radiofrequency signal caused by ferromagnetic resonance absorption. The same apparatus is used for recording by replacing the radiofrequency oscillator with a direct current source and by modulating the tickling field with the signal to be recorded.
Inventors
- 👤 Leonard J Schwee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:44
CPC Classifications
G; G06; G06K; G06K11/00; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B11/10534; G11B11/10539; G11B11/11; G11B11/115
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
137 words
Apparatus for reading out magnetic information recorded on a uniaxially anisotropic thin film having an anisotropic axis comprising: signal transmission line means normally separated from said thin film and oriented parallel to said anisotropic axis, and couplable to a source of high-frequency electromagnetic waves for transmitting said high-frequency electromagnetic waves across said thin film; means for effecting relative movement between said thin film and said signal transmission line means, whereby the entire area of said thin film passes within close proximity to said signal transmission line means; means for effecting modulation of said high-frequency electromagnetic waves by said magnetic information; means coupled to said signal transmission line means for demodulating and for phase detecting the modulated highfrequency electromagnetic waves to produce a direct current output signal having an amplitude proportional to the amplitude of said magnetic information.
Claim 2
Dependent Claim
137 words
Apparatus for reading out magnetic information recorded on a uniaxially anisotropic thin film having an anisotropic axis comprising: signal transmission line means normally separated from said thin film and oriented parallel to said anisotropic axis, and couplable to a source of high-frequency electromagnetic waves for transmitting said high-frequency electromagnetic waves across said thin film; means for effecting relative movement between said thin film and said signal transmission line means, whereby the entire area of said thin film passes within close proximity to said signal transmission line means; means for effecting modulation of said high-frequency electromagnetic waves by said magnetic information; means coupled to said signal transmission line means for demodulating and for phase detecting the modulated highfrequency electromagnetic waves to produce a direct current output signal having an amplitude proportional to the amplitude of said magnetic information.
Claim 3
Dependent Claim
23 words
Apparatus as in claim 1 wherein: said signal transmission line means comprises a grounded conductive plate, and a conductor positioned adjacent said plate.
Claim 4
Dependent Claim
18 words
Apparatus as in claim 1 wherein: said means for effecting relative movement comprises a constant speed conveyor belt.
Claim 5
Dependent Claim
24 words
The apparatus of claim 1, further comprising: means coupled to said demodulating and phase detecting means for visually displaying said direct current output signal.
Claim 6
Dependent Claim
41 words
The apparatus of claim 1, wherein said means for effecting modulation comprises a plurality of field coils connectable to a source of alternating current potential for exposing said thin film to a low-frequency magnetic field oriented parallel to said anisotropic axis.
Claim 7
Dependent Claim
69 words
The apparatus of claim 5, wherein said demodulating and phase detecting means comprises: a radiofrequency demodulator coupled to said signal transmission line means for demodulating said high-frequency electromagnetic waves; a phase-sensitive detector connectable to said source of alternating current potential and coupled to the output of said radiofrequency modulator for comparing the output of said radiofrequency modulator to said alternating current potential to produce said direct current output signal.
Claim 8
Independent Claim
107 words
A method of reading out magnetic images recorded on a uniaxially anisotropic thin film comprising the steps of: transmitting high-frequency electromagnetic waves through a transmission line positioned parallel to the anisotropic axis of said thin film; effecting relative motion between said thin film and said transmission line; applying a low-frequency magnetic field to said thin film to modulate said high-frequency electromagnetic waves by said magnetic images in response to the presence of low-frequency magnetic field; demodulating the modulated high-frequency electromagnetic waves; and phase detecting the demodulated high-frequency electromagnetic waves to produce a direct current output signal having an amplitude proportional to the amplitude of said magnetic images.
Claim 9
Independent Claim
107 words
A method of reading out magnetic images recorded on a uniaxially anisotropic thin film comprising the steps of: transmitting high-frequency electromagnetic waves through a transmission line positioned parallel to the anisotropic axis of said thin film; effecting relative motion between said thin film and said transmission line; applying a low-frequency magnetic field to said thin film to modulate said high-frequency electromagnetic waves by said magnetic images in response to the presence of low-frequency magnetic field; demodulating the modulated high-frequency electromagnetic waves; and phase detecting the demodulated high-frequency electromagnetic waves to produce a direct current output signal having an amplitude proportional to the amplitude of said magnetic images.
References Cited (Backward Citations)
US3354447A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |