Design And Implementation Of Wireless Data Transmission System Based On DSP

Software Defined Radio (SDR) is wireless communication system which based on communication, digital signal processing and micro-electronics technology. The devices configuration can be realized by means of software, and the functionality can be improved through software upgrade. Software defined radio technology provides an efficient and comparatively inexpensive solution.π/4-DQPSK modulation is a linear narrowband technology which possesses features of high spectrum utilization ratio, better spectrum specification, stronger anti-fading and anti-jamming performance. So this modem method has been widely employed in mobile communication system, satellite communication system.Firstly, the features ofπ/4-DQPSK technology was introduced generally and modulation/demodulation theory, bit synchronization implement approach ofπ/4-DQPSK are depicted in detail, the result of simulation is given in these chapter. Then a new design of full-duplex narrowband communication system based on DSP, CMX981, CMX992, CMX993 is introduced. Channel codecs, bit-streaming processing and synchronous extracting which can be implemented in DSP. Data extraction/interpolation and filter can be realized by CMX981. Meanwhile, transceiver up/down conversion and radio frequency amplification can be realized by CMX992 and CMX993. The system has the characteristics of low power, high spectrum utilization ratio, and supports portable application.