Design of a Wideband Frequency Agile Synthesizer

This paper introduces an design of frequency agile synthesizer which combines the direct frequency synthesis technology of analog and digital methods. Firstly, the DDS generates a low frequency signal which has low phase noise and fast frequency switching time, and then the harmonic generators provide the high frequency local oscillator signals to mix with the output of DDS, which realize the signal spectrum shifting and band broadening. Finally it generates a fast-switching signal with the bandwidth of 14~20GHz, frequency step of 0.5MHz, switching time less than 150ns, phase noise better than −100dBc /Hz@1kHz, and the spurious suppression better than −65dBc.