An electronic circuit capable of producing a waveform that rises abruptly, maintains a relatively flat top for an extremely short interval, and then rapidly falls to zero. A relaxation oscillator, such as a multivibrator, may be adjusted to generate a rectangular waveform having an extremely short duration, and as such it is referred to as a pulse generator. However, there is a class of circuits whose exclusive function is generating short-duration, rectangular waveforms. These circuits are usually specifically identified as pulse generators. An example of such a pulse generator is the triggered blocking oscillator, which is a single relaxation oscillator having transformer-coupled feedback from output to input.
Pulse generators sometimes include, but are usually distinguished from, trigger circuits. Trigger circuits generate a short-duration, fast-rising waveform for initiating or triggering an event or a series of events in other circuits. In the pulse generator, the pulse duration and shape are of equal importance to the rise and fall times. See Trigger circuit
The term pulse generator is often applied not only to an electronic circuit generating prescribed pulse sequences but to an electronic instrument designed to generate sequences of pulses with variable delays, pulse widths, and pulse train combinations, programmable in a predetermined manner, often microprocessor-controlled.
A network, formed in such a way as to simulate the delay characteristics of a lossless transmission line, and appropriate switching elements to control the duration of a pulse form the basis for a variety of types of pulse generators. Some delay-line-controlled pulse generators are capable of generating pulses containing considerable amounts of power for such applications as modulators in radar transmitters. See Wave-shaping circuits