High spectrum purity signal source applied in X-band radar frequency criterion generator

Abstract

A high spectrum purity DDS-PLL signal source applied in X-band radar frequency criterion generator is introduced. It's specifications list the following: output frequency range 8500 MHz/spl sim/9800 MHz; hopping step 1 kHz; hopping points 1,000,000; phase noise <-80 dBdHz@10 kHz. A novel and particular scheme is introduced, a good many mutual inconsistent factors can be satisfied simultaneously by using this method, and the specification's requirements can be achieved. The scheme is based on a DDS-PLL hybrid frequency synthesizer. The measurement results are presented. On the basis of the measurement result, the distribution characteristics of the output spectrum are analyzed.