Sanyo Electric Co., Ltd.

Nippon Hoso' Kyokai

Yoshihiko Morita

Hiroshi Watanabe

Toshiaki Hioki

Tateo Toyama

Minoru Yasuda

Shigekazu Minechika

Makoto Yamada

Haruo Isono

A two-side video disc is manufactured by laminating a top side face disc having a HDTV video signal with red color signal component recorded and a back side face disc having a HDTV video signal with blue color signal component recorded at a position corresponding to the recorded signal on the top side face. Visual end marks are formed at the respective ends of recording tracks of the top side face and back side face discs. The two discs are laminated so that the positions of the end marks coincide with each other. This minimizes deviation in timings between the reproduced signals from the two sides of the disc to reduce significantly the memory capacity of a delay circuit.

Two-sided video disc having high definition television video signals

Stereoscopic video disc record and recording and reproducing apparatus

A frequency multiplexing circuit in an optical video disc recorder frequency-multiplexes a second signal comprising a digital sound signal on the low frequency band of a first signal comprising a frequency-modulated video signal to generate a recording signal. In addition, the recording signal is applied to a limiter to be limited. In this case, a noise component produced in a band of the second signal is extracted by using a Bessel filter and a subtractor and previously subtracted from the recording signal generated by frequency multiplexing. The recording signal including a negative noise component is applied to the limiter, so that harmonic noise and linear distortion noise essentially produced in an output of the limiter can be cancelled. Furthermore, a slice level of the limiter is suitably adjusted, so that asymmetrical noise in the output of the limiter can be also eliminated.

Frequency multiplexing circuit in optical video disc recorder

Growing community of inventors

Gifu, Japan

Yoshihiko Morita