Takaharu Noguchi

Digital Signal Processing Technology For R-DAT

As one of consumer audio equipment, the CD (Compact Disc) player has come into wide use since its commercialization of 1982 for its high quality sound, easy operation and low price. The Direct Broadcasting Satellite (DBS) service has started in Japan in 1984. On the other hand, the Digital Audio Tape recorder (DAT) which has both recording and reproducing function and easy recording from these digitalized audio sources, is expected to be a next-generation audio product.

A new concept of DATA/DAT system

Presents the DATA/DAT system, which is based on the high-density recording and reproducing technology and digital processing technology of the DAT (digital audio tape recorder) system. This system has various applications, such as replacement of the conventional magnetic tape and data streamer and data storage for image processing. To achieve data reliability, an adaptive decoding algorithm using C1, C2 decoding has been developed. As a result, even at an error rate of 10/sup -2/ after 5000 operations, an uncorrectable error probability of 10/sup -15/ has been attained. To implement the random access and update-in-place function, a group format using gap frames and after-recording technology has been developed. The system can be applied to home electronics and personal databases. >

A consumer digital VCR for advanced television

A prototype of a digital VCR for ATV (advanced television) has been developed. This VCR records the compressed digital HDTV (high-definition television) signal of the ATV system. The total recording bit rate is 36.8 Mb/s (18.4 Mb/s per channel), and the maximum recording time is 4 h with oxide tape. Thus, it is confirmed that it is possible to produce a low-cost consumer digital VCR for ATV with current VCR technology. >

A home-use digital VCR with high density modulation method

A 8-12 channel coding (modulation) method suitable for high-density recording for a home-use digital video cassette recorder (VCR) was developed. An areal recording density of 2.3 mu m/sup 2//b can be achieved by this 8-12 modulation method. A signal-to-noise ratio of 24.2 dB and a symbol error rate of about 1*10/sup -4/ were obtained experimentally on the tape-head simulator for current metal evaporated tape. >

16-BIT A/D Converter and D/A Converter for Digital Audio

The Compact Disc Player has made a rapid popularization of so called digital audio using a PCM technique. And this fall, Digital Audio Tape-recorder (DAT) is expected to be commercialized. The A/D and D/A converters are two of key devices for DAT, so it is required to realize high performance, low cost and low power consumption.

A Study On The Method on Double The Data Rate For Recording/reproducing And Search Speed For DAT

A method to double the search speed and the data transmission rate for recording/reproducing has been studied for a DAT (digital audio tape recorder). A high speed search up to 400 times the normal playback speed was realized. Using this DAT, the search time for programs from the beginning to the end of a 2-hour long tape was reduced to 26 sec from 44 sec, the latter value being that for a conventional DAT. With this technology, a high-speed search system has been developed for a DAT using magnetic tape as the recording medium. >

A Study On The Digitization Of Audio Signals For S-VHS VCR

The recording and reproducing characteristics of the PCM (pulse code modulation) audio signal, reduction of interference to the video signal by the PCM audio signal, and performance against tracking error have been studied on a digital audio system for S-VHS VCR (video cassette recorder). A block error rate of 5*10/sup -4/ is attained without degradation of both video and FM audio signals. Amorphous heads have been used for both video and audio heads and the PCM signal carrier-to-noise ratio of 19 dB in the EP mode has been obtained without degradation of the video signal. It is confirmed that the uncorrectable error rate is under 1 symbol/second even in the case of a tracking error of -20 mu m to 9 mu m in the EP mode. >