A closer look at ring diode modulators

An ideal ring diode modulator will have an output containing only frequencies of the form (n/spl omega//SUB LO//spl plusmn//spl omega//SUB m/) where n is odd and /spl omega//SUB m/ is one of the signal input frequencies. It is shown that real ring behavior is critically dependent upon the diode´s forward characteristic, in particular, the forward threshold voltage. This threshold is required to support signal potentials across the ring and together with the forward diode nonlinearity controls the switching response of the diode to applied potentials. An analysis of the ring is presented that takes these factors into account and predicts the experimentally observed product suppression maxima.