A hardware phase continuous frequency synthesiser for frequency hopping spread spectrum

One of the major problems when implementing frequency-hopping spread-spectrum systems is to obtain an accurate, fast, and transient free frequency synthesizer. Direct digital synthesis meets these requirements with economy and simplicity. A brief analysis of a direct digital frequency synthesizer is made, indicating the several sources of noise that contribute to signal degradation, the frequency distribution of spurious response due to phase and amplitude quantization, and expressions for the signal-to-noise ratio. A hardware prototype was built (using emitter-coupled logic), and its performance is shown to be in good agreement with both theoretical and simulation results based on the computation of a fast Fourier transform.<>