Yoshinobu Oba

A new 8-14 channel coding for D-3 format VTR

An 8-14 channel coding method suitable for high density recording for digital VTRs was developed. Using this coding, an 8-b data word is transformed into 14-b code word, assuming that the distance between magnetic polarity transitions is two to seven channel bits, the maximum absolute of the DSV (digital sum variation) is seven. The code has a minimum recorded wavelength 14% longer and a required bandwidth 12.5% narrower than those of S-NRZ and M/sup 2/ codes. Since it is a run-length-limited block code, it provides simplified recording and reproduction equalization, azimuth and overwrite recording, no error propagation to any other word, and error detection. The signals encoded by applying this method as well as S-NRZ and M/sup 2/ to 64-Mb/s M-sequence data were recorded and reproduced using metal particle tape and a Sendust laminated sputtered type head. The results show that the reproduced SNR of 8-14 channel coding was 2.8 dB higher than those of S-NRZ and M/sup 2/. >

New 8-14 channel coding for high-density recording

The D-3 has achieved a recorded density some 2.5 times higher than those of conventional VTRs. Channel coding, which is capable of high-density recording and is suited for the head-tape recording system, is one of todays most important high-density recording technologies, and a new 8-14 channel coding has been developed and employed for the D-3 format. The paper presents the requirements for channel coding which are required in digital VTRs and explain in detail the generation of the new 8-14 channel coding meeting these requirements, which is a type of DC-free run-length-limited block coding. It explains the actual procedure and configurations of the channel encoder/decoder for 8-14 channel coding. It also compares and examines channel coding methods that have been used until now from several aspects, and describes their features.< >

Editing Interchangeability of the Narrow Track Digital VTR.

Editing interchangeability is one of the most important factors in narrow-track digital VTRs for broadcast use. The worst degradation of the recording foot print occurs during insert editing. This work investigates all factors that can lead to format errors. Several new technologies, such as a head pair configuration, a distinctive audio sector arrangement, using a guard band only at the editing point and so on, are proposed as ways to reduce the influences of these errors. Moreover, a new definition for the tolerance zones of helical tracks is recommended. As an example of an application, the interchangeability of the D-3 format is identified.