| 摘要 |
PURPOSE:To enable highly accurate pitch detection and accurate setting of upper and lower limits of feeding pitch by simple constitution by calculating feeding pitch from the number of rotation of a discoid recording medium and feeding speed of a pickup and detecting and displaying whethr this is within the range of limiting value or not. CONSTITUTION:A signal of frequency proportionate to feeding speed of a recording pickup 11 that makes recording on a disk 1 is generated from a detector 15 and supplied to a reset signal generator 24 through a waveform shaping circuit 23. Reset of a counter 26 that counts reference clock is controlled by the generator 24, and period of a detection signal of frequency proportionate to feeding speed of the pickup 11 is measured digitally through a latch circuit 27. A microprocessor 28 calculates feeding pitch from the measured feeding speed and the number of rotation of the disk 1. This is compared with accurate upper and lower limit values obtained by processing and it is displayed in a display unit 29 whether pitch is within the range of limit value or not. As a frequency-voltage convertor etc. is not necessary, accurate detection of feeding speed pitch and setting of upper and lower limits can be made by simple constitution. |
