| 摘要 |
PURPOSE:To set optionally the duty ratio of a pulse signal whose duty ratio is not fixed by detecting the leading edge of an input pulse and generating a saw- tooth wave. CONSTITUTION:When the digital signal A whose duty ratio is not constant is supplied to a monostable multivibrator circuit 1, the leading edge of the input pulse is detected to obtain a pulse B. An operational amplifier 2 form an integration circuit together with C1 and a constant current is inputted through R2 to charge the C1. The C1 is discharged every time the pulse B is outputted, so the saw-tooth wave C appaears at the output terminal of the amplifier 2. The signal C is smoothed through R4 and C2 to obtain a mean voltage D. Then, the signals C and D are inputted to an analog comparator 3, which performs binary coding to obtain the digital signal which synchronizes with the input signal and has a 50% duty ratio. Further, the duty ratio is varied optionally by varying the ratio of the mean voltage D and saw-tooth voltage C. |
