Design And Realization Of OQPSK Modem Based On FPGA

OQPSK(Offset Quadrature Phase Shift Keying)modulation technology is a constant envelope modulation technology, which possesses features of high spectrum utilization ratio, better spectrum specification, The modem method has been employed in satellite communication system and mobile communication system.The paper designs and realizes a FPGA-Based all digital OQPSK modem, which is backgrounds all digital OQPSK demodulator of the devices for reconnaissance, in this modem, the modulator is a signal generator for simulating the unknown OQPSK signal. The paper researches the base algorithm about all digital OQPSK modem, such as pulse shaping filter, NCO model, carrier recovery and timing recovery; Completes the algorithm simulation with MATLAB. Based on this, under the ISE7.1 of Xilinx Company, Very High Speed Integrated Circuit Hardware Description Language (VHDL) has been adopted for designing and implementing every module, which is based designed hardware platform. Via fact testing, the OQPSK demodulator achieves scheduled object. The paper also implements 100M Ethernet Interface for the demodulator, which could conveniently transmit the data of demodulated to PC for monitor.