Research And Implementation Of4FSK Modulation And Demodulation Under The Software Defined Radio

Software defined radio is a new design thinking which is proposed in the late20th century. Its core idea is to build an open, standard, flexible general-purpose hardware platform, by loading software reconfigurable to achieve a variety of communication functions. Modulation and demodulation techniques is a key technology in the field of wireless communications, the merits of the modulation and demodulation algorithm can greatly affect the performance of the wireless communication system.As one kind of a constant envelope modulation,4FSK has high transmission rate, but the transmission rate to make its power reduction.4FSK signal with constant envelope features make it very beneficial when through the limit with nonlinear channel, and has many advantages including higher spectrum efficiency, amplitude and phase effect is low, and the cost is low and so on.The communication system based on software defined radio using the full digital technology, and having distinct essence with the second generation of digital receiver. It uses the general DSP hardware platform, the modulation and demodulation both need through the software to realize, this way of modem puts forward new requirements, therefore, the research of software radio modem technology has very important significance.This paper makes an in-depth analysis on4FSK modulation and demodulation algorithm, does modulation and demodulation process simulation in MATLAB simulation environment, carried out in-depth research of the shaping filter used in the modulation process, Details of the FIR filter design methods and designs the shaping filter by the FDATool, Also, the paper focus on analysis and description of the realization of4FSK modulation and demodulation in DSP platform, introduces the hardware platforms SEED-DEC6416and software development environment CCS, Using the C language achieves the4FSK modulation and demodulation in the SEED-DEC6416Plat, and shares the realization of data figure about4FSK modulation and demodulation through CCS3.1. Finally, the paper makes a comprehensive analysis for the program optimization of4FSK modulation and demodulation, proposes optimization method for the specific hardware environment which is TMS320C6416. And the realization of the code has been optimized; part of the optimization of the linear assembly code and optimized assembly code optimization has been shared.