The software radio technology has received more and more attention in military and civilian abroad in recent years, which breaking the development pattern of communication devices depends only on hardware. In China, many achievements have been made in the research of software radio and3G mobile communications has been applied, but it’s still in the initial stage, and there are many problems to be solved, therefore it is very necessary and meaningful to research on software radio technology.With the help of software radio technology, we complete the communication process of baseband signals, including modulation, transition, reception and demodulation. The modulation process is carried out in the DSP with a D/A converter, its sampling rates up to48KHz, which send the modulated signals to the oscilloscope for observation. Then, the modulated signals is sending out from the headphone interface by McBSP serial port. The signals at the receiving end is also demodulated by McBSP serial port in the DSP after the A/D conversion, which the demodulation results can be observed in CCS. The D/A and A/D is integrated in the inside of PCM3002A chip which its opening is through the start of registers.In this paper we mainly study the modulation and demodulation technology of MASK, MPSK and MQAM. As the common feature of these three modulation signals is that the amplitude or phase between code elements are different, also can call them amplitude phase signals. We start from the origin of the software radio, introduce its characteristics and development history. The secend chapter mainly introduces the basic principle of the three above modulation and demodulation technologies, then performes extensive simulations by MATLAB and analyzes the results. Third chapter realizes the three kinds of amplitude phase signals by CCS in the DSP development environment and analyzes the simulation waveforms of CCS. The forth chapter introduces detailly the hardware realization of the three above modulation and demodulation technologies. The hardware platform of system in this paper is based on the fixed-point DSP chip TMS320VC5416which is x54series of TI company. This system integrates the transmitter module with receiver module into one test board, mainly including the DSP module, CPLD module, off-chip memory module, DA/AD module and power module; especially, the DA/AD module select the voice chip PCM3002A which combine the DA/AD conversion in one, users can set the sampling rates through registers and connect with the McBSP seamlessly on hardware, thus it’s easy to operate. The fifth chapter is the realization of sending and receiving data. We can observe the modulated anolog signals that have been sent out through the oscilloscope, and process the received digital signals by CCS graphical tools, then the whole communication process is completed. Obviously, results obtained are consistend with the theoretical analysis.