S-band Broadband High-performance Frequency-hopping Source Development

As the mainstream of modern microwave frequency source implementations, Frequency synthesizer has adapted to the requirements of high performance, small size, low cost and a series of demanding, that complex electronic equipment have proposed. It's also known as the frequency synthesizer. Progressing, there are kinds of frequency synthesizers. From the initial direct frequency synthesis to today's multi-frequency synthesis, frequency source has been made great progress in high-frequency, broadband, height phase noise, low spurious, fast frequency hopping and series of other indicators. All of these inspire people to promote the technology to higher levels.In this paper, the development of frequency synthesis and microwave frequency source was proposed, and the technique of spread spectrum in frequency synthesizer was introduced, especially the technology of DDS/PLL frequency synthesis. One method was implemented by comparing and analyzing of different combination method. Through the kind of debug, test comparison, testing data, I conducted in-depth analysis to the program and conclusion.In this issue, after carefully program designing and device selecting, the bandwidth of frequency synthesizer was expanded, and good level of spurious, phase noise, frequency resolution and other key indicators were ensured by using a method of embedding DDS in PLL based on single-loop PLL, which used as fractional divider, in the S-band. Also, the function of each unit circuit was introduced, and their performances were tested in the relevant sections. And also, a great effort was conducted to improving the spurious of output frequency, through segmenting and merging output frequency of VCO, rational designing the bandwidth of Loop filter, screening output frequency of DDS, and implementing the program of digital-controlled divide frequency. And all of these induced a good effect on the final output spectrum.