accurate way for calculation of oscillation frequency

[mohammadpiano]

oscillation frequency

hello to all.
i am a beginer in RF design , please help me.
what is an accurate way for calculation of oscillation frequency
in a lc tank with ads?

 

[oermens]

Re: oscillation frequency

how about ω=1/√(LC) ?

do you mean measure/simulate using ADS? use tran or hb analysis.

 

[mohammadpiano]

Re: oscillation frequency

hi
thanks
yes i know this equation w=1/sqrt(lc)
but i want that u tell me how i can calculate oscillation
frequency of LC tank with ads?
hb? or s-parameters?
there is an example in ads for this subject but this is not
accurate.(we must plot db(s(2,1)) an the max is f0)
i used s-parameters for this goal and my answer is different
with theorical calculation.
what is my fault?
plz help me...

 

[rezaee]

Re: oscillation frequency

what kinds of equation u use for analytical calculation & what kinds of elements u use in ADS simulator?? maybe your fault is because of u use equations for ideal elements but u simulate real elements in ADS

 

[mohammadpiano]

Re: oscillation frequency

my dear rezaee, ur answer helped me
yes, my fault is here
thanks for ur attention to my question
can u explain me more about this?
best regards...

 

[rezaee]

Re: oscillation frequency

my dear rezaee, ur answer helped me
yes, my fault is here
thanks for ur attention to my question
can u explain me more about this?
best regards...

of course i dont know what equations u use but if u calculate with simple equations without attention to parasitic elements in real models of elements and if u use real elements model for ur simulation in ADS so it is clearly that the result in ADS differs with ur calculation results.
im beginner in using ADS for RF design i would be glad if i can help u. i cant tell u that exactly ur fault is for this reason but maybe it is one of the reasons.

Regards

 

[oermens]

i still think the word "calculate" is wrong. if you want to calculate the approximate oscillation frequency then use w=1/sqrt(LC). if you want exact, transient analysis in ads will tell you. the least you can do is transient analysis and put a delta marker to measure one period, then inverse is frequency. i dont use ads but there must be some calculator or function that will tell you the frequency of the entire waveform.