Sughrue, Mion, Zinn, Macpeak & Seas
Spindle servo device for data recording disk reproducing apparatus
 An apparatus for playing a composite disk containing separate audio-only and video-plus-audio portions, as well as an ordinary compact disk. It is first detected whether the disk being played is a compact disk or a composite disk, and if the disk is a composite disk, whether the portion presently being played is a region containing only audio data or a region containing a frequency modulated video signal recorded in multiplex form with a digital signal. A reference signal for driving a spindle servo circuit is produced as a fixed frequency signal when the disk is a composite disk or the region of a composite disk being played contains only audio data, and as a variable frequency signal of frequency determined in accordance with the frame sync signal contained in the reproduced signal when a region of a composite disk containing a multiplex-type signal is being reproduced. 
Pioneer Electronic Corporation
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Hidehiro Junichi Masayori Takeshi Kazuhiko Noriyoshi Osamu Masao
Ishii Yoshio Shinohara Izumo Katakami Takeya Watanabe Yoshida