an audio fm modulated wave and a video fm modulated wave respectively both the modulated waves are subjected to frequency multiplexing by circuit 6 during which oscillators 7 and 8 generate carrier signals having frequencies f 1 and f 2 wherein both frequencies are within a predetermined band outside the frequency band used for recorded audio and video information signals next carrier signals f 1 and f 2 are supplied to a selection switch 9 the selection switch 9 alternately selects carrier signals f 1 and f 2 every time the rotation detector 3 senses the disk has completed a revolution the selected carrier signal f 1 or f 2 is supplied to the multiplexing circuit 6 and the subjected to frequency multiplexing with the audio and video information signal the multiplexed signal is limited in amplitude by a limiter circuit 10 and then supplied to a light modulator 11 which turns a laser beam emitted from a laser light source 12 on and off the laser beam illuminates a photo resist surface of the master disk 1 so that pits exposed portions representing recorded information are burnt into the photo resist surface the disk 1 is made to function as a master disk recorded original disk throughout developing treatment any disk obtained from this master disk as shown in fig2 also include the carrier signals f1 the solid line and f2 the dashed line recorded on adjacent tracks within the information signal referring to a block diagram of fig3 an embodiment of the tracking error detector circuit according to the present invention for use in an apparatus for playing prerecorded disk will be described hereafter in fig3 three laser beams are radiated onto the disk 39 s prerecorded tracks to read each.