| 摘要 |
PURPOSE:To perform stable intermusic detection by controlling a gate circuit with the output of a comparator which is obtained by comparing the output signals of a reversible counting part with a numeral storage part, and the output of an intermusic detector. CONSTITUTION:A tone arm position signal generator 2 built in the controller of a tone arm generates one pulse signal for a specified extent of movement or rotation regardless of its direction and then inputs it to a reversible counting part 3 to perform arithmetic in switched addition or subtraction mode, and the output of the counting part 3 corresponds to the position of the tone arm. A numeral signal storage part 4 previously stores a numeral corresponding to the tone arm right above the lead-in part 4 of a disk according to the size of the disk. A comparison 5 between outputs of the counting part 3 and storage part 4 is made and the result is inputted to a gate 6. At this time, when the output of an intermusic detector 1 is supplied to the gate 6, the gate 6 generates an output 7. Consequently, even if an erroneous signal corresponding to a point outside of the lead-in groove of the disk is generated, the gate 6 never generates the output, so that malfunction is prevented. |
