DIGITAL MAGNETIC PICTURE RECORDING AND REPRODUCING DEVICE

Japanese Patent JPH01211372

A

PURPOSE:To make solid writing possible without increasing an azimuth angle and improve frequency utilizing efficiency and, at the same time, to make recording and reproduction without receiving any influence from reproduction distortion by recording multilevel digital codes on a magnetic recording medium after performing multilevel orthogonal amplitude modulation on the codes and decoding the codes by means of a Viterbi decoder. CONSTITUTION:A multilevel converter 2 converts n-bit digital codes into 2-value digital I signals and 2-value digital Q signals and outputs the signals to a multilevel QAM 3. The multilevel QAM 3 outputs the signals to an adder 4 after performing multilevel orthogonal amplitude modulation on the signals. The output of the adder 4 is bias-recorded on a magnetic recording medium 8 through an REC amplifier 6 and magnetic head 7. On the reproducing side, a multilevel QAM demodulator 10 demodulates multilevel orthogonal amplitude modulated signals from a head amplifier 9 into multilevel digital I and Q signals and outputs the signals to a Viterbi decoder 11. The decoder 11 performs decoding by regarding the frequency deterio ration caused by magnetic recording and reproduction as convolutional codes. Therefore, solid writing becomes possible even though the azimuth angle is not set so large and the frequency utilizing efficiency is improved. Moreover, recording and reproduction become possible almost free from influences of reproduction distortion.

SHIMOTASHIRO MASAFUMI
MATSUDA TOYOHIKO
KOBAYASHI MASAAKI
SHIMAZAKI HIROAKI

JP3817088A

August 24, 1989

February 19, 1988

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MATSUSHITA ELECTRIC IND CO LTD

G11B20/10; G11B20/18; (IPC1-7): G11B20/10

JPS61287078A

1986-12-17

Tomoyuki Takimoto

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