| 摘要 |
PURPOSE:To perform accurate detection without influence of an error due to operating characteristics of a photoelectric converting element, etc., by performing end detection through comparing the time, required to count respective edges of a two- phase position detection signal to a prescribed value, with a reference time. CONSTITUTION:A two-phase position detection signal having pulses corresponding to the extent of movement of a tone arm and having phase shift of 90 angles is supplied to counter 2. Counter 2 performs 4N-scale counting operation and of every carrier output signal performs comparing operation in data comparator 3. Data comparator 3 compares time data from a timer with reference time data from reference data generator 5 at every carrier output signal from counter 2 to output end detection speed signal. The end detection speed signal and end detection position signal are ANDed by AND gate circuit 6, which outputs an end detection signal. |
