US3883858A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetoresistive readout transducer for sensing magnetic domains in thin film memories
Assignee: Ampex Corp
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Filing: 1973-12-17
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Granted: 1975-05-13
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Expires: 1993-12-17
Abstract
Abstract A magnetoresistive bridge formed of specific magnetoresistive elements is disposed on a monolithic substrate in conjunction with a thin film shift register. At least one (active) element of the bridge is placed in the region of the last domain position in a shift register channel. At least one other (balance) element of the bridge is spaced from the magnetic structure, whereby the combination balances the bridge while compensating for temperature variations. In one embodiment, two active arms of a four-element bridge are arranged such that a bipolar sense signal is obtained as a ''''1'''' passes into the last domain position. The remaining balance elements are spaced from the magnetic structure to provide compensation for noise, as well as temperature variations. A readout circuit provides an amplifier combination which samples the bipolar signal during selected time windows to enhance the sense signal output generated by the bridge.
Inventors
- 👤 Heinz Lienhard
- 👤 Walter S Carter
- 👤 Irving W Wolf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:42
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/02; G11C19/08; G11C19/0866
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
271 words
A magnetoresistive readout system for integral disposition with readout regions of respective storage channels in a thin film storage device including first and second magnetoresistive element means formed of respective magnetoresistive thin films integrally disposed within the thin film storage device, comprising the combination of: said first magnetoresistive element means including a pair of active magnetoresistive thin film elements disposed in magnetic field coupling relation with a selected readout region of a respective storage channel; said second magnetoresistive element means including a pair of balance magnetoresistive thin film elements electrically coupled to the pair of active magnetoresistive thin film elements to define a balanced bridge configuration: wherein the bridge generates a bipolar read signal in direct response to the passage of a magnetic domain adjacent only the active elements; said second balance elements being sufficiently spaced from any storage channels to have no magnetic coupling with any magnetic domains; readout circuit means coupled to the bridge defined by the active and balance pairs of elements for generating a logic output indicative of the presence and the absence of magnetic domains in magnetic coupling relation with only the active elements; said readout circuit means including strobe means for selectively sampling the output of the bridge only during a time window commensurate with passage of the domain adjacent the pair of active elements, and differential amplifier means to provide a signal magnitude equal to the difference between the positive and negative values of the bipolar read signal generated during said time window and for generating binary logic output signals indicative of the presence or absence of a domain adjacent only the active elements.
Claim 2
Dependent Claim
271 words
A magnetoresistive readout system for integral disposition with readout regions of respective storage channels in a thin film storage device including first and second magnetoresistive element means formed of respective magnetoresistive thin films integrally disposed within the thin film storage device, comprising the combination of: said first magnetoresistive element means including a pair of active magnetoresistive thin film elements disposed in magnetic field coupling relation with a selected readout region of a respective storage channel; said second magnetoresistive element means including a pair of balance magnetoresistive thin film elements electrically coupled to the pair of active magnetoresistive thin film elements to define a balanced bridge configuration: wherein the bridge generates a bipolar read signal in direct response to the passage of a magnetic domain adjacent only the active elements; said second balance elements being sufficiently spaced from any storage channels to have no magnetic coupling with any magnetic domains; readout circuit means coupled to the bridge defined by the active and balance pairs of elements for generating a logic output indicative of the presence and the absence of magnetic domains in magnetic coupling relation with only the active elements; said readout circuit means including strobe means for selectively sampling the output of the bridge only during a time window commensurate with passage of the domain adjacent the pair of active elements, and differential amplifier means to provide a signal magnitude equal to the difference between the positive and negative values of the bipolar read signal generated during said time window and for generating binary logic output signals indicative of the presence or absence of a domain adjacent only the active elements.
Claim 3
Dependent Claim
77 words
The readout system of claim 1 wherein the active sense elements extend over the plurality of the storage channels in a single plane in magnetic field coupling relation to selected readout portions thereof; and the balance elements extend equally but in spaced relation from the storage channels; said thin film storage device including read drive lines for respective storage channels to rotate the magnetization of the domain in a selected storage channel during readout of that channel.
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) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |