MAGNETIC RECORDING AND REPRODUCING DEVICE

Japanese Patent JPS592266

A

PURPOSE:To shift a head up to its optimum position in a short time, by sending the head at a high speed until a reproduced signal is obtained, then the sending speed is lowered to give the wave detection of envelope curve to the reproduced signal, and detecting the maximum level to stop the head at the position of the maximum level. CONSTITUTION:When a magnetic head 8 moves on a magnetic sheet 9 toward a signal recording part 17b. In this case, the head 8 is shifted at a high speed via a motor control circuit 2 unitl the reproduction voltage 18 reaches up to a fixed level 19. The position information of the head 8 at that time point is calculated in the form of the number of output pulses of a rotary encoder 10 and then stored in a memory 15. Then a motor 4 is repetitively revolved at a low speed and stopped until the number of output pulses of the encoder 10 reaches a fixed level with a command given from the circuit 2. Then the head 8 is sent back to a position equivalent to the sum of the number of output pulses of the encoder 10 which is obtained the voltage 18 reaches its maximum level set by an amplifier 11 through a control circuit 16 and the number of pulses generated by the encoder 10 until the head 8 moves up to the level 19. Then the head 8 is fixed at its optimum position.

FUJITA NAOYA
TAKEDA KATSUNOBU

JP10840682A

January 07, 1984

June 25, 1982

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HITACHI LTD

G11B21/10; G11B5/55; (IPC1-7): G11B21/10

Toshiyuki Usuda

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