×

Optical record carrier having position indentifying track modulation

  • US 4,907,216 A
  • Filed: 12/09/1987
  • Issued: 03/06/1990
  • Est. Priority Date: 07/10/1987
  • Status: Expired due to Fees
First Claim
Patent Images

1. Apparatus for recording and/or reading an information signal in an elongated track on an optical record carrier, which track is modulated by a periodic position-identifying signal having a frequency which is synchronous with a clock signal, said position-identifying signal identifying the locations of successive positions along said track;

  • such apparatus comprising means for scanning said track with a beam of radiation which is reflected therefrom, optical detecting means for detecting the reflected beam and generating a detection signal corresponding to the modulation of such beam caused by the track modulation, and a detection circuit for deriving said position-identifying signal from said detection signal;

    characterized in that;

    said position-identifying signal comprises successive digital code signals at successive locations on said track the same as those where said information signal is recorded thereon, each digital code signal being in the form of modulated excursions of said track in a direction substantially transverse thereto; and

    said position-identifying signal is in a frequency band substantially outside the frequency band of said information signal.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×