Pulse generator for producing a pulse having a pulse width dependent on an input signal

摘要

In a pulse generator responsive to an input pulse, use is made of a time constant circuit having a time constant for charge and a time constant for discharge considerably greater than the former. The time constant circuit is rapidly charged during presence of the input pulse in accordance with the time constant for charge, through a switching circuit kept on, while it is slowly discharged in accordance with the time constant for discharge after the switching circuit is rendered off due to disappearance of the input pulse. During charging and discharging, the time constant circuit gives a variable level to a threshold circuit for producing an output pulse when the variable level exceeds a threshold level. The output pulse lasts until the variable level is rendered less than the threshold level after disappearance of the input pulse. Additionally, the pulse generator comprises a combination of a constant current portion and a constant voltage portion to stabilize the input and output pulses. The pulse generator is suitable for a noise pulse canceller for a radio receiver.