Hopping In The Software Radio Research And Hardware Implementation

Software Radio was proposed by Joe Motila on May 1992 with the purpose of solving the following problems in wireless communication: the co-existing multiple systems, the competition between several communication standards, the lack of bandwidth and the rapid growth of personal communication.Applications of Software Radio in radio station resulted in the development of Wireless Transceiver. This thesis focused on frequency hopping part of the Military Wireless Transceiver that is under searching and development. Frequency hopping technology has the capabilities of anti-interference and anti-interception. And it can increase the bandwidth efficiency as well. Furthermore, it become more and more important in commercial wireless communication because it can reduce the effects imposed by multi-path fading and co-channel interference.The core of a frequency hopping system is the frequency synthesizer. Its hopping speed and hopping patterns are the key factors for the overall performance of the communication system. The essential requirements for the frequency synthesizer are: 1).low side band power 2).high hopping speed 3).short convergence timeDirect Digital Synthesis technology has the advantages of low cost, low power consumption, high frequency discrimination and short switching time.This thesis presents the implementation of a high-speed frequency hopping system in DDS+PLL structure. A DSP is used to generate quasi-stochastic sequence and control the output frequency to construct required hopping maps.