COMPARISON OF CFA's FOR PULSED-RADAR TRANSMITTERS.

The six basic types of high-power CFA's are reviewed for use in pulsed-radar transmitters. It is observed that the types of CFA's needing the simplest pulse modulators have been the least used in field equipment so far. This apparent conflict is explained on the basis that other factors dominate the selection of CFA type. These factors are the effect of CFA arcs on system operation, the method required to regulate the HVPS, and the method of limiting droop during long-pulse operation. Cathode-pulsed CFA's have generally been preferred because the type of modulator used with them offers simpler solutions to these other factors. Dc-operated CFA's (control-electrode or RF-keyed) thus tend to be used only when they can offer performance capabilities that are impractical to obtain from cathode-pulsed CFA's. Several case histories supporting this viewpoint are presented.