How to clip the calculator dft() output ?

Vishal,

How about using the value() function if  you want to pick a particular frequency? Or using the clip function to find a range, and then ymax to find the peak?

Regards,

Andrew.

Hi Andrew,

Thanks for the hint.

value() did not work . May be I am using it wrong.  I will look into the syntax and try it out again for dft() output.

But using clip() on dft() output and ymax() search worked fine. ymax() can not handle complex numbers.

dft()  output is a complex number and hence need to find peak in the real part and peak in the imaginary part.

Then take the magnitude of two outputs.

vop=value(getData("VOUT") 'vamp 10m)

vop_dft=dft( vop 500n 1.9u 4096 "Rectangular")

clip_vop_dft=clip(vop_dft 1.190G 1.192G) ;;; My peak is located at 1.191G

ymax_real=ymax(real(clip_vop_dft))

ymax_imag=ymax(imag(clip_vop_dft))

ymax_tot=sqrt(ymax_real*ymax_real + ymax_imag*ymax_imag)

Any comments on the above

Regards,

Vishal

Vishal,

Finding the ymax of the real and the ymax of the imaginary is definitely wrong. There's no guarantee they will be at the same frequency, so the result you get is potentially completely wrong.

It would be batter to use:

ymax_tot=ymax(mag(clip_vop_dft))

However, I don't see why value shouldn't work (it does for me). I'd do:

mag(value(vop_dft 1.191G))

The mag function essentially the abs() - which does the sqrt(real**2+imag**2).

Regards,

Andrew.

Hi Andrew ,

Thanks for the correction and for solution to value() .

I was trying to use value() from calculator function list !!

Regards

Vishal