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How to improve phase noise in cmos LC vco ?

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Re: Phase Noise

Try the noise filter by E.Hegazi, it's an inductor sunting the current source.
 

Re: Phase Noise

to improve phase noise u need to know how every noise source contribute in VCO phasenoise , and decide which one need to be minimized ,

filter the current source or filter the bias voltage ,
or u need to optimize the varactor layout for minimun serise resistance , improving the coil quality factor

khouly
l
 

Re: Phase Noise

there is a tradeoff between tuning range and phase noise.
i think u can try to optimize the Q of ur tank
 

Re: Phase Noise

obovolo said:
there is a tradeoff between tuning range and phase noise.
i think u can try to optimize the Q of ur tank
Click to expand...

hi
i think contribution of phase noise is c&L. Is there any other thing which can cotribute phase noise.
please help..
 

Re: Phase Noise

Other noise source is the reference oscilator. Add a series 3 to pole Band PAss filter to your reference .
VCO noise ( if using comercial VCO) is inherent and not much can be done.
To get the lowest noise, usually the shunt capacitor( cap to ground) in the loop filter has to be a big value ( 22uF) . This improves noise,but time locking is delayed.
 

Re: Phase Noise

obovolo wrote:
there is a tradeoff between tuning range and phase noise.
i think u can try to optimize the Q of ur tank
Click to expand...

Heard that for many years.
If someone can povide textbook or literater seriously dealing with this subject.
I have a question:
YIG resonator has wide tuning range and excellent phase noise.
what's the trade-off then?

Hope I'm not confusing anybody.
 

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