An Improved Method Focusing on X-Band Low Phase Noise Sweep Source

This paper proposes a method to improve the phase noise of a X-band sweep source. It is based on a PLL(Phase-locked loop) circuit driven by a DDS(Direct Digital Synthesizer), and an offset source is introduced in the PLL circuit. The DDS is used to generate low-frequency sweep signal, the PLL circuit is used to multiply the low-frequency sweep signal, and the offset is introduced to decrease the phase noise. This method decreases the phase noise of the sweep source greatly.