[SOLVED] How to plot the Q of a filter from the S-parameter simulation with Spectre

[wht4665453123]

Dear all,

I have run an S-parameter simulation with Spectre in Cadence and got the S21 of a filter. Can anybody tell me how to plot the Q, which is defined as 3.14*freq*d(phase(S(2,1)))/d(freq)
BTW, the differential term in that definition is also called Group Delay.

My friend told me to export the data into MATLAB and plot the Q. I wonder whether there's a easier way to do it?

I suppose I should use the Calculator tool in Cadence, but I'm not familiar with it.

Thank you very much.

 

[BigBoss]

In Cadence Design Environment, "freq" variable being as in ADS is NOT defined, therefore it's almost impossible to draw a curve vs. freq.
But I don't know the recent versions, it could be refined ...
The easiest way to draw this, import s-parameters in MatLab and then define the equation and draw it..
Or, use RFDE ( ADS working in ADE ) and plot this curve as in ADS...

 

[pancho_hideboo]

In Cadence Design Environment, "freq" variable being as in ADS is NOT defined,

Correct.

therefore it's almost impossible to draw a curve vs. freq.
But I don't know the recent versions, it could be refined ...

Wrong.
In Cadence Spectre, "freq" is avaliable as xval(s(2,1)).

See https://www.edaboard.com/threads/208177/

Can anybody tell me how to plot the Q, which is defined as 3.14*freq*d(phase(S(2,1)))/d(freq)

Q=( 2*acos(-1)*xval(s(2,1)) )/2 * abs( groupDelay(s(2,1)) )

 

[wht4665453123]

I got it working. Thank you very much.