Based On Software Radio Frequency Hopping Radio Modem Design

According with the development of communication technology, wireless communication in military requires higher performance, such as high data rate and integrated anti-jamming ability. Recently, frequency-hop communication has been widely used in many military wireless communication domains as a secure transmission mode. Meanwhile intercommunication and joint fighting among different military forces need an open, expandable, normalized software and hardware platform. Therefore the idea of software defined radio has been widely used in it.This thesis proposes an entire solution of modulation and demodulation, which is implemented on the physical layer of the VHF radio based on the software defined radio and frequency hopping technology. The project mainly uses FPGA+DDS hardware circuit to achieve the radio modem: when the radio emission, the use of GMSK modulation, FPGA internal signal directly to baseband frequency to radio frequency, produced with the DDS chip FPGA to control the RF modulated analog waveforms, followed by filtering and amplification can be sent to the antenna terminal; when radio reception, FPGA generates the first control the DDS frequency hopping synthesizers, as a radio channel amplifier board down-conversion LO signals, then A/D sampling IF signals in internal FPGA digital down-conversion, demodulation and other functions.The program has been applied in the new VHF frequency-hopping radio, the radio through the test validated the program to meet the needs of performance to achieve the desired design goals. The program proved simple and feasible, with certain applications and reference value.