A simple run-length limited NRZI code is proposed. To limit the run-length, a special transition is inserted into the boundary of the code cell when all 4 successive data are 0__-s. Except this condition, a data 1__- consists of a normal transition in the center of the code cell as in conventional NRZI code. The maximum run-length is 4.5Tb. where Tb is the data period. To remove the special transition, analog signals from a playback equalizer are convertedto 2 bit digital data every clock period Tc(Tc=Tb) and decoded.
A new ROM-type digital optical disk produced by the current Laser Disk mass production process and a player system for the disk have been developed. The disk system has a data transfer rate of about 2Mbyte/sec and a storage capacity of 7.1Gbyte/side(30cmCLV), and its physical format is independent of the contents being recorded on it . As an application of the disk system , we have developed the HDTV Digital Still Picture Filing System.
We have developed a professional DAT system which keeps compatibility with a consumer DAT and has several functions for professional use. This paper is concerned with technical points of the professional DAT system, mainly record/playback method of IEC timecode , 4 head mechanism for confidence monitor , electronic editing and chase synchronization.