Abstract:A method to develop a frequency synthesizer with high spurious suppression, high frequency resolution and low phase noise is discussed.This design is based on the blended frequency synthesizer theory.A Sband frequency synthesizer has been fabricated.The experimental result shows that the frequency resolution is 100Hz,phase noise is better than -115 dBc/Hz@10 kHz,spurious suppression is more than 80 dBc and frequency switching time is 140 μs.