Design And Implementation Of IF/Baseband Module For DMR/dPMR Digital Teminal

Digital Mobile Radio (DMR) and digital Private Mobile Radio (dPMR) are thelatest global open standards for digital radio developed by the EuropeTelecommunication Standards Institute (ETSI) in2005and2006. Employing4FSKmodulation and TDMA2-slot structure, DMR has high spectral efficiency and simpleimplementation structure. DMR support multi-layer applications from direct modecommunication to trunked system. The long response time of the oscillator and LC filter,coupled with low stability and linearity of frequency detector in traditional analog FMmodulation restricts the performance of multi-slot system such as DMR. Base onSoftware Defined Radio technology, this paper puts forward and implements a kind ofdigital IF module for DMR terminal. This module can improve the accuracy andresponse time with its digital frequency modulation design.dPMR standard employs FDMA structure. With its channel bandwidth as6.25KHz,dPMR has double bandwidth efficiency of current general12.5KHz narrow-bandsystem.This paper improves the first edition of DMR baseband module and implentsdPMR interphone on it.This paper first introduces the main technical characters of DMR/dPMR standardsand basic principles of digital IF signal processing. Then it elaborates the overall IFmodule design and the hardware implementation with FPGA and DSP as mainprocessing chips. Later the hardware circuit is tested and the Digital Up Conversion(DUC) module is designed and implemented in FPGA with HDL language. The DUCmodule mainly consists of interpolation filter and Numerically Controlled Oscillator(NCO). Test results shows the IF board meet system desire and the up conversionmodule can work.Finally the dPMR interphone implementation is introduced.