微波EDA网,见证研发工程师的成长!
首页 > 研发问答 > 微波和射频技术 > 天线设计和射频技术 > VCO How can I lower Phase Noise?

VCO How can I lower Phase Noise?

时间:04-04 整理:3721RD 点击:


I have the VCO schematic above. I need a tuning frequency of 2.35G to 2.55G and phase noise to be below -115dbc at 1MHz. Right now I have the Phase Noise at -111dbc. I read somewhere that you can add a capacitor to the drain of the tail transistor to short the AC noise and then add an inductor in series with the transistor and resonate it at 2f0. However, when I tried this it actually made the noise worse. Are there other methods of improving noise? I have minimized the two oscillator transistors already. Any suggestions would be greatly appreciated. Thanks!

Anyone have tips on whether nmoscap or pmoscaps have less phase noise and should i use normal nmos or lvt or hvt transistors for the oscillator?

having high Q main resonant tank will help reducing phase npise.

You can check Leeson formula for phase noise or you can read about the linear time variant theory of phase noise published by Thomas Lee and Ali Hajimiri. Otherwise, you can better the phase noise increasing the Q of your resonant LC circuit, increasing the power dissipation or adjusting the size of your transistors to reduce thermal noise as you did. Maybe it is not a great practice, but you can use the parasitic capacitance of the inductors to tune the frequency of oscillation without the use of capacitors, in order to reduce thermal noise and increasing the Qloaded. Hope it will help

上一篇:How Lo Nulling Works?
下一篇:最后一页

Copyright © 2017-2020 微波EDA网 版权所有

网站地图

Top