宽带跳频信号源的设计

Design of a wide band frequency-hopping signal generator

对于现有频率合成方法难以产生同时具备宽频带和高速频率跳变能力信号的问题,提出一种基于直接数字频率合成和直接频率合成技术的频率合成方案。首先推导了步进频率信号合成原理,分析了跳频系统实现原理,并介绍了设计方案以及测试结果,最终实现了小步进带宽为100 Hz、大步进带宽为67 MHz、总带宽为1 GHz、跳频时间小于20 ns的高速步进频率信号源,该方案杂散抑制较好,相位噪声-100.78 dBc/Hz@10 kHz,实现简单,性能优良。

In this paper,a frequency synthesis concept based on direct digital synthesis（DDS） and direct synthesis technology is proposed.As it is difficult for the current frequency synthesis method to generate a wideband and high-speed frequency hopping signal.The principle of stepped-frequency signal synthesis is investigated,the theory of hopping-system realization is analyzed,and design method and test result are provided.A 100 Hz small step-frequency and 67 MHz big step-frequency signal generator is realized,with its bandwidth is 1.0 GHz and frequency hopping interval less than 20 ns.The spurious suppression is good,phase noise is -100.78 dBc/Hz@10 kHz.It could be easily realized and the performance is perfect.