| 摘要 |
PURPOSE:To make it possible to synchronize a high-speed clock frequency by performing Schmitt triggering by waveform-converting an AND output signal between a signal to be synchronized and a clock pulse and by operating a switch when this signal exceeds a certain value. CONSTITUTION:Data of a signal to be synchronized and a clock pulse are inputted to NAND circuit 9, whose AND output signal is inputted to the waveform converting circuit composed of resistance R and capacitor C to prolong the rise time of the AND output signal. The waveform-converted signal is inputted to Schmitt trigger circuit 6. When the output of trigger circuit 6 reaches a prescribed level, switching transistor 10 connected in parallel to resistance R is made operated to short-circuit resistance R. Therefore, the voltage at point A rises suddenly and trigger circuit 6 turns the circuit off. Thus, the existence of data is judged securely, so that a high- speed clock frequency can be synchronized. |
