A Review of SAW-Based Direct Frequency Synthesizers

Many new electronic systems, including spread spectrum links, require frequency synthesizers capable of providing accurate signals of high spectral purity, and must be able to change frequencies in fractions of a microsecond. Three such synthesizers based on comb generators, SAW filterbanks, and fast switches are reviewed. Each of these synthesizers can provide an output at approximately 1.3 GHz from one of over 200 frequencies of integral megahertz value.