A Contribution to the Design of a Frequency Synthesizer for Fast Frequency-Hopped Spread-Spectrum Systems

Techniques of the using of digital frequency locked loop (DFLL) in the frequency-hopped spread-spectrum (FH-SS) systems are presented. The approach, presented in this paper, makes it possible to use an accurate DFLL in place of RF local oscillator (LO) especially in the fast FH-SS systems. A DFLL in place of LO has not been reported for fast FH-SS systems mainly because that type of frequency synthesizer requests relatively long time to accurate frequency measuring and setting. Using the predicting algorithm in DFLL lead to solution of this problem. Application of the predictive digital frequency locked loop (PDFLL) in place of LO in fast FH-SS systems makes it possible to use advantageous spectral properties of the DFLL.