The present invention concerns a pulse generator circuit for forming very narrow pulses with extremely low jitter or phase noise. More particularly, the pulse generator circuit of the present invention requires only NPN type transistors, such transistors being readily available for use at microwave frequencies.
Sampled phase locked loops require stable local oscillator circuits which are frequency and waveform agile and have low phase noise. The gating pulse of the sampler is used to turn on the diodes of a double balanced mixer and thus gate an RF signal to a load. In such an application, the gate pulse generator must have extremely low noise and jitter characteristics, and provide a moderate current output, say 30 milliamperes.
Pulse generating circuits are presently known which are low noise circuits and provide moderate current output pulses. Examples of such circuits are shown in the drawings herein. However, the generation of narrow width pulses, in the order of one nano-second or less, is precluded by their use of one or more PNP transistors, which are not generally suitable for such high speed switching applications.