Design of a Wideband Agile Frequency Synthesizer for the S-C Band Based on DDS

The agile frequency source based on direct digital synthesizer (DDS) has become a critical component in high-speed frequency-hopping anti-jamming communication due to its ultra-short frequency switching time, enabling hop rates greater than code rates. This paper proposes a frequency planning method to achieve a high spectral purity agile frequency synthesizer in the range of 3.43-5.73GHz. Experimental results show that the frequency synthesizer has a switching time of less than 10ns, a spuriousfree dynamic range greater than -53dBc, and phase noise values of -91.5dBc/Hz, -92.6dBc/Hz, -101.3dBc/Hz, and -123.5dBc/Hz at frequency offsets of 1kHz, 10kHz, 100kHz, and 1MHz, respectively when outputting 4.00GHz. These results fully validate the feasibility of the proposed method.

基于直接数字合成器（DDS）的捷变频源，凭借其极短的频率切换时间，已成为高速跳频抗干扰通信领域的关键组件，可实现高于码率的跳频速率。本文提出一种频率规划方法，可在3.43~5.73GHz频段内实现高频谱纯度的捷变频合成器。实验结果表明，该合成器在输出4.00GHz信号时，切换时间小于10ns，无杂散动态范围优于-53dBc，且在1kHz、10kHz、100kHz及1MHz的频率偏移处的相位噪声分别为-91.5dBc/Hz、-92.6dBc/Hz、-101.3dBc/Hz与-123.5dBc/Hz。上述结果充分验证了所提方法的可行性。