Title:
MODULATION AND MODULATION SYSTEM
Document Type and Number:
Japanese Patent JPS618779
Kind Code:
A
Abstract:
PURPOSE:To eliminate the influence of an oscillation waveform and to widen an amplitude margin by performing converting modulation when ''1'' which is not original information is written by the modulation demodulation system of (1,7) or (2,7) encoding codes, and performing recovery modulation when it is read. CONSTITUTION:An encoder 8 converts NRZ write data into encoded data with (1,7) or (2,7) encoding codes. When a ''0'' detecting circuit 9 detects the succession of six or seven pieces of information ''0'', two center pieces of information ''0'' are converted by a ''1'' converting circuit 10 into information ''1'', which is written on a recording medium by a magnetic head 2. Information read by the head 2 during reading operation is inputted to a ''1'' detecting circuit 12 and a ''0'' converting circuit 13 converts two successive pieces of information ''1'' into information ''0'' when the succession of two pieces of information ''1'' are detected. Then, a decoder 14 reconverts the (1,7) or (2,7) encoded data into the original write data, thus removing the influence of the oscillation waveform and widening the amplitude margin.
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Inventors:
AIKAWA TAKASHI
MUTOU HIROSHI
MUTOU HIROSHI
Application Number:
JP12832084A
Publication Date:
January 16, 1986
Filing Date:
June 20, 1984
Export Citation:
Assignee:
FUJITSU LTD
International Classes:
H03M5/14; G11B20/14; H04L25/49; (IPC1-7): G11B20/14; H03M5/14; H04L25/49
Attorney, Agent or Firm:
Sadaichi Igita
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