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.