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MSK modulation by virtue of the continuous phases , the envelope constant , narrow bandwidth, and other characteristics are widely used in various communication systems . MSK modulation technology , MSK modulation of the high-speed broadband technology is already quite mature , large-scale application in the HF band . But the of narrowband low rate MSK modulation technique is not perfect , there are many difficulties in the hardware implementation is not resolved , therefore , this paper focuses on research for of narrowband low rate MSK modulation and demodulation . Firstly focusing MSK modulation and demodulation principle and simulation performance of various modulation methods , according to the simulation results , the method to determine the frequency of direct synthesis MSK modulation . Several demodulation algorithm followed by a detailed study of the MSK demodulator for demodulation performance and hardware realization of several demodulation algorithm analysis and comparison , and the performance of the various demodulation algorithm the simulation . The final analysis of the factors affecting the performance of the MSK demodulator : a carrier sync, bit sync , frame sync . Under the conditions determined in the demodulation algorithm , a detailed study of the carrier synchronization , bit synchronization , frame synchronization algorithm , and is given in the the existing carrier synchronization algorithm based on an improved algorithm . Full digital processing , using a combination of DSP and FPGA the modem hardware design , data collection, computing , synthetic all digitized . The digital platform also allows the modem to have a lot of flexibility and scalability . After the completion of the actual hardware , we also do made ??some auxiliary measurement equipment , the help of these devices , the performance of the entire system , and various test data were analyzed and compared .
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