Distortion effects in a switching-diode modulator with tuned terminations

Abstract

Analysis previously developed for the prediction of distortion outputs in broadband switching-diode mixers and modulators handling multifrequency inputs is modified to include the effects produced by tuning both source and load terminations. The compensation theorem is invoked to replace the sideband tuned circuits by equivalent generators. An important consequence of tuning the modulator terminations is shown to be the appearance of distortion products absent from the output spectra of the broadband-terminated circuits. Good agreement is demonstrated between theoretical predictions and the measured outputs from typical series and shunt modulators operating at high frequency.