A New Optical Videodisc System with One Hour Playing Time

A series of papers proposing a possible format for reflection-type optical videodisc systems was published in 19761-3. Principal parameters of the format (with NTSC standards) are as follows: the disc rotation speed is 1800 rpm, the track-to-track pitch is 1.67¿m, and the playing time is 30 minutes from one side of a 12-inch-diameter disc. A direct frequency modulation of the composite NTSC video signal is employed, with the attractive feature that the full extent (4.2 MHz) of NTSC luminance bandwidth can be retained in this format.