PURPOSE: To detect which part of an EFM signal recording carrier is scanned by modulating a track modulating frequency according to position information signals alternately arranged with position synchronizing signals. CONSTITUTION: The track modulating signals are modulated according to position information signals, but position information signals are provided with position code signals 12 alternately appearing with position synchronizing signals 11, and respective position code signals 12 are made to express 38 code bit position information code modulated into two-phase mark modulation having the length corresponding to 76 channel bit. The 38 bit position information code is made to express the time required for covering the distance from the starting point of the track to the point where the position information signals are positioned at the nominal scanning speed. By this way, position code signals expressing the scanning momentary position are simply reproduced.
OPTICALLY READABLE AND PROGRAMMABLE RECORDING CARRIER AND ITS MANUFACTURE AND APPARATUS FOR RECORDING/REPRODUCING INFORMATION BY USING SUCH RECORDING CARRIER