What is the difference between a pulsed amplifier and a CW amplifier?
The most obvious difference lies in the ratio of peak to average power capability. A good quality pulsed amplifier that is rated for say 1kW pulsed power at 10% duty-cycle, will contain just as many power transistors as a 1kW CW amplifier. However, the power supply and cooling requirements for the pulsed amplifier are much less, since it is rated for only 100W average power. Apart from that, RF amplifiers that are designed for pulsed operation include many features and specifications that will not be found in CW amplifiers. Pulsed amplifiers include high-speed noise gating, which reduces the output noise level to almost zero in-between pulses. This is important in applications such as NMR or radar, in which the inter-pulse signal levels of interest are extremely small. Pulsed amplifiers generally must be capable of reproducing pulses with very fast rise and fall times, while amplifiers designed for CW operation often do not have that capability.
