EP0053343A1
Expired / Lapsed
EP
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Reproducing and amplifying circuit for magnetoresistive head
Assignee: Hitachi Ltd
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Filing: 1981-11-24
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Granted: —
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Expires: 2001-11-24
Abstract
Abstract A reproducing and amplifying circuit for a magnetoresistive head (10) comprises an amplifying circuit (30, 40, 50, 51, 52) with a feedback circuit (31, 70, 90). The head is connectable with the feedback circuit so that the head is supplied with a drive current by the amplifying circuit and that a reproduced electric signal outputed by the head is coupled to the amplifying circuit for amplification: A magnetoresistive element (70, 80, 90) may be provided in the amplifying circuit to effect temperature compensation for the head. The reproducing and amplifying circuit is simple in structure, has an enhanced signal-to-noise ratio and is immune to temperature variation.
Inventors
- 👤 Takao Arai
- 👤 Takaharu Noguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 11:24
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3945; G11B5/02; G11B5/027; G11B5/03; H; H03; H03F; H03F3/00; H03F3/181; H03F3/183; H03F3/187
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
130 words
A reproducing and amplifying circuit for a magnetoresistive head (10) engageable with a magnetic recording medium (4) for reproducing an electric signal from magnetization in said recording medium, comprising circuit means for amplifying said reproduced electric signal derived from said head, said amplifying circuit means including an amplifier circuit (30, 40, 50, 51, 52) and a feedback circuit (31, 70, 90) for said amplifier circuit, in which said feedback circuit is provided with means for electrical'connection with said head thereby for supplying a drive current to said head and coupling said reproduced electric signal to said amplifying circuit means for its amplification, and said amplifying circuit means has such a circuit structure that in operation the voltage at the junction of said head and said feedback circuit is held constant.
Claim 2
Dependent Claim
130 words
A reproducing and amplifying circuit for a magnetoresistive head (10) engageable with a magnetic recording medium (4) for reproducing an electric signal from magnetization in said recording medium, comprising circuit means for amplifying said reproduced electric signal derived from said head, said amplifying circuit means including an amplifier circuit (30, 40, 50, 51, 52) and a feedback circuit (31, 70, 90) for said amplifier circuit, in which said feedback circuit is provided with means for electrical'connection with said head thereby for supplying a drive current to said head and coupling said reproduced electric signal to said amplifying circuit means for its amplification, and said amplifying circuit means has such a circuit structure that in operation the voltage at the junction of said head and said feedback circuit is held constant.
Claim 3
Dependent Claim
49 words
A reproducing and amplifying circuit according to Claim 1, in which said amplifier circuit includes a differential amplifier (30) having a non-inverted input terminal for receiving a fixed potential and an inverted input terminal for electrical connection with said head by said electrical connection means in said feedback circuit.
Claim 4
Dependent Claim
53 words
A reproducing and amplifying circuit according to Claim 1, in which said amplifier circuit includes an electronic amplifying element (40) having a control electrode for receiving a fixed potential, an electron collecting electrode and an electron emitting electrode for electrical connection with said head by said electrical connection means in said feedback circuit.
Claim 5
Dependent Claim
126 words
A reproducing and amplifying circuit comprising a magnetoresistive head (10) engageable with a magnetic recording medium (4) for reproducing an electric signal from magnetization in said recording medium and circuit means for amplifying said reproduced electric signal derived from said head, said amplifying circuit means including an amplifier circuit (30, 40, 50, 51, 52) and a feedback circuit (31, 70, 90) for said amplifier circuit, in which said head is connected with said feedback circuit thereby for supplying a drive current to said head and coupling said reproduced electric signal to said amplifying circuit means for its amplification, and said amplifying circuit means has such a circuit structure that in operation the voltage at the junction of said head and said feedback circuit is held constant.
Claim 6
Dependent Claim
126 words
A reproducing and amplifying circuit comprising a magnetoresistive head (10) engageable with a magnetic recording medium (4) for reproducing an electric signal from magnetization in said recording medium and circuit means for amplifying said reproduced electric signal derived from said head, said amplifying circuit means including an amplifier circuit (30, 40, 50, 51, 52) and a feedback circuit (31, 70, 90) for said amplifier circuit, in which said head is connected with said feedback circuit thereby for supplying a drive current to said head and coupling said reproduced electric signal to said amplifying circuit means for its amplification, and said amplifying circuit means has such a circuit structure that in operation the voltage at the junction of said head and said feedback circuit is held constant.
Claim 7
Dependent Claim
44 words
A reproducing and amplifying circuit according to Claim 4, in which said amplifier circuit includes a differential amplifier (30) having a non-inverted input terminal for receiving a fixed potential and an inverted input terminal in electrical connection with said head in said feedback circuit.
Claim 8
Dependent Claim
29 words
A reproducing and amplifying circuit according to Claim 4 or 5, in which said feedback circuit includes a magnetoresistive element (70, 80, 90) for temperature compensation for said head.
Claim 9
Dependent Claim
84 words
A reproducing and amplifying circuit according to Claim 6, in which each of said magnetoresistive head (100) and said magnetoresistive element (200) includes a pair of metal strips (102, 121, 202) and a ferromagnetic strip (103, 203) having its ends fixed to first ends of said metal strips to be formed in a U-shape as a whole, said drive current flowing from second end of one of said pair of metal strips through said ferromagnetic strip to second end of the other metal strip.
Claim 10
Dependent Claim
39 words
A reproducing and amplifying circuit according to Claim 7, in which one of said pair of metal strips of said magnetoresistive element is constituted by an extension of one of said pair of metal strips of said magnetoresistive head.
Claim 11
Dependent Claim
48 words
A reproducing and amplifying circuit according to Claim 4, in which said amplifier circuit includes an electronic amplifying element (40) having a control electrode for receiving a fixed potential, and electron collecting electrode and an electron emitting electrode in electrical connection with said head in said feedback circuit.
Claim 12
Dependent Claim
48 words
A reproducing and amplifying circuit according to Claim 9, in which a magnetoresistive element (80) is connected with said collecting electrode of said amplifying element so that said magnetoresistive element serves both as a load resistor of said amplifying element and as a temperature compensation element for said-head.
Claim 13
Dependent Claim
79 words
A reproducing and amplifying circuit according to Claim 10, in which each of said magnetoresistive head and said magnetoresistive element includes a pair of metal strips (102, 121, 202) and a ferromagnetic strip (103, 203) having its ends fixed to first ends of said metal strips to be fomed in a U-shape, said drive current flowing from second end of one of said pair of metal strips through said ferromagnetic strip to second end of the other metal strip.
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