Magnetic reproducing system

• US 4,464,691 A
• Filed: 08/05/1981
• Issued: 08/07/1984
• Est. Priority Date: 08/13/1980
• Status: Expired due to Term

• Current Assignee: Tokyo Shibaura Denki Kabushiki Kaisha (Toshiba Corporation)
• Original Assignee: Tokyo Shibaura Denki Kabushiki Kaisha (Toshiba Corporation)
• Inventors: Chiba, Shu, Sawazaki, Norikazu
• Primary Examiner(s): Canney, Vincent P.
• Application Number:
  US06/290,325
• Time in Patent Office: 1,098 Days
• Field of Search: 360/29, 360/30, 360/55, 360/111
• US Class Current: 360/111
• CPC Class Codes: G11B 5/33 Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing onlySingle head using magnetic domains for scanning G11B5/4946; multiple head for scanning G11B5/4907 and subgroups ; general details therefor G11B5/133 - G11B5/255
• CPC Class Codes: G11B 5/332 using thin films G11B5/372, G11B5/3903 take precedence

Abstract

A magnetic head includes a magnetic body, at least the permeability or high frequency loss of which is changed with changes of the record magnetic field on a magnetic tape, and a coil. A high frequency signal is supplied to a tuned circuit, which includes the coil and a capacitor, and a signal corresponding to the record magnetic field is taken out through the detection of the changes of the voltage of the high frequency signal supplied to the tuned circuit.

Claims

1. A magnetic reproducing system comprising:

a magnetic head having a magnetic body buried in a molding which serves as a head base, in such a way that it is partly exposed and is in frictional contact with a magnetic recording medium, and a strip coil buried in said molding in such a way that it is electromagnetically coupled with said magnetic body, and the edge of said strip coil on one side thereof is in the vicinity of said magnetic body; and

means for obtaining a reproduced signal across said strip coil according to changes in a record magnetic field of said magnetic recording medium, wherein said reproduced signal obtaining means has a tuned circuit including said strip coil, a pair of conductive film divisions provided on said head base and connected to opposite ends of said strip coil, and a tuning capacitor connected between said pair of conductive film divisions, means for supplying a high frequency signal to the tuned circuit and means for deriving a signal corresponding to said record magnetic field through the detection of changes in the voltage of the high frequency signal supplied to said tuned circuit.

2. The magnetic reproducing system according to claim 1, wherein said strip coil is a U-shaped strip coil buried in said molding in such a way that it surrounds said magnetic body.

3. The reproducing system according to claim 1 or 2 wherein bias magnetic field generating means is burried in said molding at a position thereof in the vicinity of said magnetic body.

4. The reproducing system according to claim 1 or 2, wherein said magnetic body is made of a magnetic material, the permeability of which changes greatly with changes in the record magnetic field, and changes in the voltage of said high frequency signal resulting from changes in the tuning frequency of the tuned circuit, due to changes of the permeability, may be detected.

5. The reproducing system according to claim 1 or 2, wherein said magnetic body is made of a magnetic material, the high frequency loss in which is greatly changed with changes in the record magnetic field, and changes in the voltage of said high frequency signal resulting from changes in the quality Q of the tuned circuit, due to the changes of the high frequency loss, may be detected.

6. A magnetic reproducing system comprising:

a magnetic head having a magnetic body with a coil wound thereon; and

means for obtaining a reproduced signal across said coil according to changes in the record magnetic field of said magnetic recording medium, wherein said means for obtaining a reproduced signal having a tuned circuit including said coil, means for supplying the high frequency signal to the tuned circuit and means for deriving a signal corresponding to said record magnetic field through the detection of the changes in the voltage of the high frequency signal supplied to said tuned circuit; and

wherein said magnetic body is made of a magnetic material, the high frequency loss of which is greatly changed with changes in the record magnetic field, and changes in the voltage of said high frequency signal resulting from changes in the quality Q of the tuned circuit, due to the changes of the high frequency loss, may be detected.

7. The reproducing system according to claim 6, wherein said magnetic body is provided in the magnetic path of a magnetic core having a gap.

8. The reproducing system according to claim 7, wherein the coil wound on said magnetic body is arranged in such a way that the high frequency magnetic field generated from the coil and the magnetic field generated from the record magnetic field are perpendicular to each other.

9. The reproducing system according to claim 7, wherein a pair of permanent magnets for biasing are provided in said magnetic path on opposite sides of said magnetic body, the magnetic field from said permanent magnets from biasing being perpendicular to the magnetic field from the recording medium.