| 摘要 |
PURPOSE:To perform normal demodulation under no influence of a change in tape speed due to disturbance by integrating a digital signal having pulse width modulated by use of a counter that can count up and down. CONSTITUTION:Pulse-width-modulated digital signal (a) is inputted to increase- decrease control terminal 9 of counter 6 and also to rise detecting circuit 5, the output pulse of which is applied to reset terminal 10. Counter 6, reset to initial value (n) when signal (a) is inputted, counts up in the pulse-width t7 period extending over one pulse cycle of data [0] and counts down to the contrary in the remaining period t8 up to a point right before arrival of the next data [1]. Therefore, the count value, the output of counter 6, is less than reference (initial) value (n) in the end of data [0] and no pulse is outputted from comparator 8. Consequently, holding circuit 4 can output an invariably normal demodulated signal without being influenced by disturbance. |
