# US 5,349,478 A · Magnetic recording and/or reproducing method having a double azimuth head arrangement

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- Number: US 5,349,478 A
- Document ID: US5349478A
- Status: Granted
- Kind: A
- Application number: 08/032,015
- Filed: 1993-03-16
- Granted: 1994-09-20
- Earliest claimed: 1992-03-31
- Assignees: Sony Corporation
- Inventors: Kenichi Sato; Kazunobu Chiba
- Web page: https://patentgrep.com/patent/US5349478A

## CPC

- G11B 5/534: {inclined relative to the direction of movement of the tape, e.g. for helicoidal scanning}
- G11B 5/02: Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

A magnetic recording and reproducing method for enhancing picture quality and other characteristics while suppressing the difference in reproduction output between two heads. The method involves using a double azimuth head arrangement for signal recording and reproduction by helical scan. The two heads A and B are provided so that their azimuth angles .theta..sub.A and .theta..sub.B do not coincide with each other. The actual recording direction represented by the sum of the azimuth angles .theta..sub.A and .theta..sub.B on the one hand and a still angle .alpha. between the heads A and B on the other is made as close to the direction of magnetic particle orientation on the magnetic recording medium as possible.

## Claims

### Claim 1

A magnetic recording and/or reproducing method for recording and/or reproducing signals on a magnetic medium by helical scan with a double azimuth head arrangement containing two heads, said magnetic medium having a coating of magnetic particles aligned in a longitudinal direction with respect to said magnetic medium, said heads scanning respective tracks inclined at an angle .alpha. relative to said longitudinal direction, one of said two heads having an azimuth angle of .theta..sub.A and the other of said two heads having an azimuth angle of .theta..sub.B, wherein .vertline..theta..sub.A .vertline..noteq..vertline..theta..sub.B .vertline., such that .vertline..beta..sub.A .vertline.-.vertline..beta..sub.B .vertline..ltoreq.10.degree., where .beta..sub.A =.vertline..alpha.+.vertline..theta..sub.A .vertline..vertline. and .beta..sub.B =.vertline..alpha.-.vertline..theta..sub.B .vertline..vertline..

### Claim 2 (depends on 1)

A magnetic recording and/or reproducing method according to claim 1, wherein said azimuth angles of said heads are formed such that said .vertline..theta..sub.A .vertline. and .vertline..theta..sub.B .vertline. have respectively different angles of at most 30.degree..

### Claim 3 (depends on 1)

A magnetic recording and/or reproducing method according to claim 1, wherein said azimuth angles of said heads are formed such that .alpha.+.vertline..theta..sub.A .vertline. and .alpha.-.vertline..theta..sub.B .vertline. are respectively different angles of at most 30.degree..

### Claim 4 (depends on 1)

A magnetic recording and/or reproducing method according to claim 1, wherein said magnetic particles are coated on said magnetic medium by oblique evaporation.

### Claim 5

Apparatus for magnetically recording and/or reproducing signals on a magnetic tape comprising: a double azimuth head arrangement containing two heads for scanning oblique tracks across said tape, the magnetic tape having a coating of magnetic particles substantially aligned in a longitudinal direction of said tape and the oblique tracks being inclined at an angle a with respect to said longitudinal direction, one of said two heads being formed with an azimuth angle .theta..sub.A and the other of said two heads being formed with an azimuth angle .theta..sub.B, wherein .vertline..theta..sub.A .vertline..noteq..vertline..theta..sub.B .vertline., such that .vertline..beta..sub.A .vertline.-.vertline..theta..sub.B .vertline..ltoreq.10.degree., where .beta..sub.A =.vertline..alpha.+.vertline..theta..sub.A .vertline..vertline. and .beta..sub.B =.vertline..alpha.-.vertline..theta..sub.B .vertline..vertline..

### Claim 6 (depends on 5)

The apparatus of claim 5 wherein said azimuth angles of said heads are formed such that said .vertline..theta..sub.A .vertline. and .vertline..theta..sub.B .vertline. have respectively different angles of at most 30.degree..

### Claim 7 (depends on 5)

The apparatus of claim 5 wherein said azimuth angles of said heads are formed such that .alpha.+.vertline..theta..sub.A .vertline. and .alpha.-.vertline..theta..sub.B .vertline. are respectively different angles of at most 30.degree..