The Relative Magnitudes of Modulation Products in Rectifier Modulators and some Effects of Feedback

The various modulation products occurring in series, shunt and ring modulators are evaluated for square-wave switching of the rectifiers. It is assumed throughout that the modulator terminations are resistive, but not necessarily the same, at the frequencies of the modulation products; their value at other frequencies is, of course, immaterial. The case when the square-wave function has unequal mark/space ratio is discussed for each of the modulators when the terminations are constant resistances. Graphs are given of the ratios of the most important products for three common classes of termination. Finally, two feedback modulator circuits for use with rectifier modulators are examined, and it is shown that a knowledge of the relative magnitudes of the modulation products in these circuits enables effective designs to be made.