Digital frequency synthesizer/modulator for continuous phase modulations with slow frequency hopping

This paper gives a description of a modulator for burst-by-burst carrier frequency hopping in TDMA systems. The architecture consists of a digital frequency synthesizer/modulator for a broad class of continuous phase modulations (CPMs) and a fast frequency settling RF synthesizer consisting of one phase-locked-loop (PLL). The performance of the digital frequency synthesizer/CPM modulator has been analyzed theoretically and simulated by a computer program. The analyses show that the proposed digital frequency synthesizer/CPM modulator achieves lower power consumption and spurious levels than the fast frequency hopping systems synthesizing digitally a full frequency band. In the computer simulations the effect of the digital frequency synthesizer/CPM modulator parameters on the power spectrum and the phase error is investigated