Direct digital frequency synthesizer for a FH spread spectrum system: analysis and design

A complete characterization of direct digital frequency synthesizers; (DDFSs) is made, deducing exact expressions and general properties of these synthesizers. As an application example of the derived expression for the power spectrum density with phase quantization, an extremely simple algorithm is described that sequentially computes the frequency and magnitude of each component and gives exactly the, same result as an FFT. Expressions for the signal-to-noise ratio, including phase and amplitude quantization, and general design rules are also presented. An ECL (emitter coupled logic) hardware prototype was built, and its performance is shown to be in good agreement with both theoretical and simulation results.<
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