The Development Of Wideband Small-step Frequency Source

Today's electronic systems are updated quickly,and each time they are upgraded,their performance indexes will be improved qualitatively,which puts forward higher requirements on the performance of the frequency source,requiring it to have a wider output bandwidth,smaller frequency step,shorter conversion time,higher spur and harmonic suppression,and lower phase noise,and requiring low power consumption,light weight,miniaturization and other characteristics.This thesis addresses the problems of narrow output frequency range,large frequency stepping,and long frequency conversion time of existing RF microwave frequency sources.Combining theoretical analysis,simulation calculation,and experimental verification,a comprehensive research has been conducted on designing techniques such as wideband output,high resolution and agile tunability.The main research work of this thesis includes:1.A 0.05~3GHz wideband small-step frequency source based on a fractional-N phase-locked loop is designed by using a fractional frequency synthesis scheme.The minimum frequency step of the frequency source in the operating frequency band is 2Hz,the spur suppression is higher than 70 dBc,the frequency conversion time is less than 95?s,and the output power is more than 2.94 dBm,and the phase noise is less than-90dBc/Hz@1kHz,-93dBc/Hz@10kHz.2.By adopting a variable reference source to drive a phase-locked loop frequency synthesis scheme,a 0.1~15GHz ultra-wideband small-step frequency source is designed.The measured results show that the minimum frequency step is 3Hz,the far-end spur suppression is higher than 50 dBc,the frequency conversion time is less than 100 us,the output power is more than-0.88 dBm,and the phase noise is less than-80dBc/Hz@1kHz,-91dBc/Hz@10kHz.3.Based on the design of 0.1~15GHz ultra-wideband small-step frequency source,combining with frequency multiplication technology and substrate integrated waveguide filter design technology,a small-step frequency multiplication source has been developed.The operating frequency range of this frequency multiplication source is 24.25~26.65 GHz,the minimum frequency step is 5Hz,the far-end spurious suppression is higher than 50 dBc,the output power is more than 10.78 dBm,the frequency conversion time is less than 100 us,and the phase noise is less than-75dBc/Hz@1kHz,-83dBc/Hz@10kHz.