raymond
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Posts: 2
singapore
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Thanks! Paul,
Yes, you are right. The 60Khz is in the 1/f3 region. And all other circuits were switched off when I did the measurement. So I suppose the substrate is quite. But the VCO circuit itselt contents two basic blocks, one is the bias circuit, another is the CCO(current control OSC).
I got the Spectre parameter from our customer. It seems they have all those 1/f parameter.
Below is my Spectre Model ..... //$*mosfet bsim3v3 noimod=2 & 3 noise parameters: + noimod=2 + noia=8.7526e+19 + noib=79484 + noic=-9.997e-13 + ef=1.06 + em=98174560 ......
1) I was wondering the big difference between the simulation and measure result. So I add the RC extaction to my netlist to account the coupling effect between the noisy signal (CCO part) and quite signal(BIAS part). But the result from the RC extraction is still more or less same.
2) So I am wondering the power supply sharing between the BIAS circuit and CCO circuit will cause the big difference.
3) Even I am wondering the substrate coupling.
Since all those published papers never mentioned the the coupling effects, power supply noise and substrate noise when they describe the phase noise in oscillator. They only theoretically analyse phase noise coming from the device noise(1/f noise, thermal noise and so on).
So I confuse that for a long while. Does that means the power supply noise, coupling noise and substrate noise are not important in analysis of the phase noise of OSC?
Do you have reference paper on that topic?Have you encounter same problem before? Any suggestions? Thanks for your help!
Raymond
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