Title :
Digital frequency synthesizer/modulator for continuous-phase modulations with slow frequency hopping
Author_Institution :
Lab. of Signal Process. & Comput. Technol., Helsinki Univ. of Technol., Espoo, Finland
fDate :
11/1/1997 12:00:00 AM
Abstract :
This paper gives a description of a modulator for burst-by-burst carrier frequency hopping in time-division multiple-access (TDMA) systems. The architecture consists of a digital frequency synthesizer/modulator for 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 2.5-W lower power consumption and 18-dB lower 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
Keywords :
access protocols; continuous phase modulation; digital radio; digital simulation; frequency hop communication; frequency synthesizers; modulation; modulators; phase locked loops; simulation; time division multiple access; 2.5 kW; PLL; TDMA systems; bandlimited communication system; burst by burst carrier frequency hopping; computer program; computer simulations; continuous-phase modulation; digital frequency synthesizer/modulator; fast frequency settling RF synthesizer; low power consumption; performance analysis; phase error; phase-locked loop; power spectrum; slow frequency hopping; time division multiple access; Computer architecture; Computer simulation; Continuous phase modulation; Digital modulation; Frequency modulation; Frequency synthesizers; Modulation coding; Phase locked loops; Radio frequency; Time division multiple access;
Journal_Title :
Vehicular Technology, IEEE Transactions on
