On the measurement of nanosecond recovery time in receiver protectors

The measurement of the recovery period in multistage receiver protectors is analyzed. It is shown that the accepted IEEE definition is unsatisfactory for the recent class of fast-recovery receiver protectors. We consider here the problem encountered when the recovery period is roughly equal to the falltime of the main transmitter pulse. It is found that accurate measurements are possible only when the reference point for the recovery measurement is taken at the singular power point located on the falling edge of the transmitter pulse which is equal to the extinguishing power of the stage which has the longest recovery period. Consequently, an alternate definition is offered which is adequate for all classes of duplexers and receiver protectors.