Immittance monitoring apparatus

摘要

Apparatus for monitoring the voltage, current, and phase of an RF signal in a transmission line. A current measuring section having a low input impedance is coupled to the transmission line and employs an isolation amplifier stage of two bipolar transistors in push-pull to produce an output signal representing the current in the RF signal. A voltage measuring section having a high input impedance is coupled to the transmission line and employs an isolation amplifier stage of two field effect transistors in a series cascade arrangement to produce an output signal representing the voltage of the RF signal. The sections include coaxial delay lines of different lengths to compensate for different internal propagation delays so that the phase relationship between the output signals representing voltage and current is the same as in the RF signal being monitored.