Masato Nagasawa

A disturbance suppression control system for car-mounted and portable optical disk drives

The paper presents a new optical drive system incorporating acceleration disturbance suppression control in the focus actuator. The new system uses a disturbance observer based on modern control theory to provide a wide range of detection. As a result, it has achieved a significant improvement in control robustness from conventional systems. >

An Experimental Home-use Digital VCR With Three Dimensional DCT And Superimposed Error Correction Coding

An experimental digital VCR system for home use is described. A high-quality moving picture is obtained by a newly developed bit rate reduction technology, which is based on subband and three-dimensional DCT (discrete cosine transform) coding. A high-density magnetic recording method which adopts a 12-to-15 modulation scheme and superimposed error correction coding enable sufficient recording time with a small cassette. Component video signals with a ration of 4:2:2 were compressed to about the ratio of 1/7, keeping a high quality, using the subband and 3-D-DCT coding method. >

A digital VCR deck mechanism using new precision actuators for high density recording

A VCR deck mechanism using high-performance actuators has been developed for high-density recording. ME (metal-evaporated) tape and laminated Sendust heads are used to raise the linear recording density, a moving-head actuator permits narrow track recording and playback, and thin tape media of 8 mu m thickness are employed. The track density is 4200 TPI when the recording wavelength is 0.53 mu m. The tape transport mechanism has realized a tape tension ratio (capstan/cassette-out) of 4.7. A rotary cylinder containing a moving-head actuator has been developed to accurately trace a 6 mu m track pitch, 78 mm track length with a control band of 300 Hz. A newly developed tape transport adjustment method based on measuring tape buckling deformation damage has been proposed which ensures the stability of 8 mu m-tape running for the deck. >

A Study of Scalable Image Coding for Digital Video Disk.

MPEG2をベースにしたディジタルビデオディスクの画像符号化方式として, 良好な早送り再生が可能な階層符号化の検討をシミュレーションにより行った.本稿では提案方式の検討の概要と良好な早送りの実現を可能としたデータ処理手法について述べる.