| Application of software-defined radio in radio station resulted in the development of wireless transceiver. Frequency hoping technology has the capabilities of anti-interference and anti-interception. And it can increase the bandwidth efficiency 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 time. direct digital synthesis technology has the advantages of low cost, low power consumption, high frequency discrimination and short switching time.Based on ad9954, a highly integrated frequency synthesizer using advanced DDS technology by ADI company, this paper introduces the operation and application theory of AD9954 in frequency hopping system. The frequency hopping system based on software-defined radio. A DSPs is used to generate quasi-stochastic sequence and control the output frequency of DDS to construct required hopping maps. Meanwhile, this theory is quite feasible in experiment. |
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