| 摘要 |
<p>Apparatus for use in a signal recovery system for recovering a video signal from a video disc, the signal including luminance information, chrominance information and periodic chrominance bursts having a prescribed amplitude, wherein the signal is recorded in a succession of light reflective and light non-reflective regions forming a plurality of substantially circular and concentrically arranged tracks, and therein the system includes a focusor for a beam of radiation onto a selected track as the disc is rotated at a prescribed angular velocity and a detector for detecting a reflected beam of radiation having an intensity modulated by the recorded video signal, the gain of the higher frequency portion of the spectral response of the signal recovery system decreasing as the radius of the selected track decreases, thereby causing a corresponding variation in the respective amplitudes of the chrominance and luminance portions of the recovered video signal, the apparatus operating to correct for the variable gain of the system by controllably amplifying the corresponding portion of the frequency spectrum of the recovered video signal, the apparatus comprising: a detector for detecting the amplitude of the successive chrominance bursts in the recovered video signal and for producing a corresponding control signal; and an amplifier for amplifying the video signal recovered from the disc, the control signal being coupled to the amplifier to controllably adjust its gain for a frequency band corresponding to the higher frequency portion of the recovered video signal, thereby correcting for the variable gain of the signal recovery system.</p> |
