A rewritable digital video disc recorder, using four optical heads on both sides of a 30cm disc which improves the data transfer rate up to 128Mbps for phase change rewritable media, has been developed. We achieved 19GB large capacity which realizes 20 minute composite digital video signal recording, with new double sided multi-head MCAV method and high density mark edge recording.

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This study proposes a new recording compensation method for mark-edge recording on rewritable phase-change optical disks. The method is composed of two techniques : improvements of the recording waveform using high speed pulse-chains and a pattern adaptive compensation which controls the edge position of the recording waveform in real-time. The former reduces the edge-shifts at the direct overwrite recording and the latter corrects the edge-shifts occurred in a specific pattern of the recording data. As a result we achieved the recording density of 1.46 bit/μm^2 and the bit error rate less than 1.0 × 10^<-5> at the overwrite conditions of the data rate of 18-46Mbps and the velocity of 10-27m/s.

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To make a controller smaller and less costly, a digital controller has been developed for Magneto-Optical (MO) head drive system equipped with a MO disk system. Lead-Lag filter with delay stabilizies higher-order resonance on MO head drive system. Repetitive controller and band-pass filter improve the level of periodic signal in control error. Applying the controller, we get completely dependable control operation and fine reproduced signal.

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The D-5 VTR, whose design is based on the D-3 format, is a high-picture-quality full-bit recording VTR using 1/2" tape. This paper deals with the need for a full-bit recording VTR and gives an outline of the D-5 signal processing format. In an environment of degradation-free 10-bit digital component processing, it is necessary to record all the bits within 10-bit signal onto the tape. D-5 employs several new technology to accomplish this full-bit recording. D-5 will fully show it's ability of full-bit recording in the degradation-free environment.

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Recently, Head-Tape Interface Technology for VCR is well studied. This paper describes Multiple heads-thin tape contact for High Density and High Datarate Recording. According to the study, head wear is proportional to normal force on multiple heads and running distance by diffrent rotational speed of cylinder. And variation of reproduced signal level by measurement using Spectrum Analyzer is related to tape stiffness ratio(MD/TD).

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