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With the rapid development of software radio technology and digital signal processing technology , the all-digital modem technology has been widely used. π/4-DQPSK modulation its own advantages , so better performance than QPSK and OQPSK modulation . For example, it can use the non- coherent demodulation , fast synchronization signal anti- fading performance is stronger than the signal , the design of the system will become easier than most systems . In this paper, the the π/4-DQPSK modulation and demodulation system . First π/4-DQPSK modulation scheme QPSK, OQPSK two modulation noted that the significant advantages of the π/4-DQPSK modulation scheme , noted that attention and widely used . Basic principle of the π/4-DQPSK modulation in MATLAB π/4-DQPSK modulation and demodulation system simulation , and obtained π/4-DQPSK in additive white Gaussian noise channel BER performance curve , verify the reasonableness of the design of the system compared with the theoretical curve . Secondly, FPGA implementation of the various modules in the system , including interpolation and decimation filter and voltage controlled oscillator (NCO), gives a waveform the realization diagram and simulation , so the design is closer to reality . Finally , in the System Generator platform system complete design , debug and download into the development board , the debugging results showed that the system design is reasonable .
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