The Key Technologies Of High-speed Frequency Hopping Communication System And Baseband Design

The system of frequency hopping is one of the spread frequency communications. It is broadly used in military and civil fields because of its near-far resistance and anti-jamming ability.This dissertation researches the fast frequency hopping system and accomplishes the design of the system and the baseband realization. The system chooses 2FSK modulation manner and appropriate hopping bandwidth from the aspect of mirror frequency restraining. It also researches the key techniques of frequency hopper, frequency hopping sequence, bit synchronization, hopping pattern synchronization, hopping signal demodulation and so on in baseband design. This dissertation adopts DDS as frequency hopper, m sequence as PRN sequence, leading-lag method as bit synchronization, TOD information method as hopping pattern synchronization. It uses duality frequency method to realize the wide interval of hopping frequency. Finally, it realizes the baseband design of a high speed frequency hopping system with 40Khps based on the SDR in the PCB composed of DSP, FPGA, DDS, ADC and so on.The hopping sequence of this system has reached upon 40Khps, which is keeping ahead in this industry. The key modules are excellently performed and have uniform interfaces which can stably work. They could assemble the baseband part of several digital communication systems and have great significance in the future research and realization.