Research And Implementation On Baseband Transmission Critical Technology In DCR System

The digital intercom is replacing analog walkie-talkie, which has become a trend for thefuture development of radio technology. The formulation of digital intercom agreement andthe key of the baseband transmission technology are the hot spots of current research, andchannel coding technology is one of the key technologies of digital intercom. The DCRinterphone standard was established for digital business interphone market by ICOM,KENWOOD and other Japanese manufacturers and so on, it was based on the digital PrivateMobile Radio. DCR standard uses the real low cost way to provide users with the bestpossible solutions for communication needs.This paper mainly has study on baseband transmission technology based on DCRstandard. The DCR system has absorbed the advantages of dPMR system channel codec way,at the same time, proposed a new coding scheme encoding scheme that the error correctionperformance is better, improved the ability to control channel transmission errors. The articleintroduces the baseband transmission technology and the corresponding physical layer anddata link layer content firstly, including FDMA multiplexing channel mode, the interval ofphysical channel, the division of logical channel and composition, frame structure, thefrequency modulation and demodulation, channel coding scheme and so on. And then, thecodec scheme and the punctured convolution codec based on DCR protocol method wasstudied, and have been analyzed the ber of the different kinds of error correction codectechnique in detail. Finally, based on standard DCR presents a scheme of digital intercom,Combining speech coding chip, radio frequency circuit and other peripheral circuit built asoftware radio platform which is mainly to realize baseband signal processing. The paperimplements the DCR channel coding scheme in the DCR standard based on the software radioplatform.