Shinichi Fukuda

A novel metal detector using the quality factor of the secondary coil for wireless power transfer systems

A novel foreign-metal detection-system for wireless power transfer (WPT) is described. Foreign metal was heated only when placed between the primary coil and the secondary coil. By having the metal in that position, the quality factor of the secondary coil (Q2) decreased rather than other parameters, so Q2 was a suitable parameter for detecting the metal. We developed s Q2 measurement circuit that works without any battery in the secondary device, and also developed a prototype WPT system with the Q2 measurement circuit. Using this system, foreign metal that might be heated could be detected before heating.

A new play-back method for R-DAT using 'non-tracking' signal processing

The authors have developed a nontracking signal processing method for a playback-only rotary-head digital audio tape recorder (R-DAT). The technique of nontracking signal processing and the technical specifications of LSIs to realize the system are described in detail. The method does not employ the AFT control described by Hitomi et al. (ibid. vol.32, no.3, 1986). The main purpose of R-DAT tracking control is to keep both a reasonable error rate and a constant tape speed. The error rate is controlled by multiscanning tracks, and the tape-speed is controlled by managing the buffer RAM. >

Recording at a channel rate of over 200 Mb/s in a helical-scan tape system

In order to increase the channel rate in a helical-scan tape system, we have studied its recording characteristics using a magnetoresistive read head, a metal-in-gap write head, and a metal evaporated tape, and transmission through a rotary transformer. A sufficient signal-to-noise ratio for the streamer system was obtained in a test drive at a channel rate of 200 Mb/s. The potential of achieving a channel rate exceeding 200 Mb/s using a thin-film write head was also investigated.