Antenna tuner discriminator

摘要

A simple technique and circuit is disclosed to replace prior Z- theta type discriminators in supplying the loading and phasing control signals to the impedance matching network in an automatic antenna tuner. The new circuit samples forward and reflected voltage Vf and Vr (or equivalently If and Ir) in the RF input. The loading control signal is supplied according to the in-phase component of Vr relative to Vf. The phasing control signal is supplied according to the quadrature component of Vr relative to Vf. The magnitude of each of the in-phase and quadrature Vr components is reduced to zero by the matching network to thus reduce the phasor amplitude of Vr to zero and hence eliminate reflected voltage.