Direct SAW Frequency Synthesizer

A frequency synthesizer utilizing three elementary direct synthesizers to achieve fast frequency hopping among 219 tones is described. The elementary synthesizers used for the two 9-channel sets of tones consist of a comb generator followed by a surface acoustic wave (SAW) filterbank and a high speed 1 x 9 switch. Although this comb generator plus filterbank synthesizer is limited to cases in which the required frequencies are evenly spaced, this in fact does not prove to be very restrictive. The scheme is conceptually simple, and has significant advantages which are enumerated. Comparison is made with the mixed chirp synthesizer. (Author) Presented at 1977 Ultrasonics Symposium, IEEE n77ch1264-1SU p511-513 Oct 77.