Shield

[Davor]

I'm still wondering what you may need white noise for. The way to make simulation noise sources more Gaussian, you may use the Box-Mueller algorithm. You need two independent random variables for it.
For a simple noise source in LTspice you may use an arbitrary behavioural voltage source, and assign voltage as a function V=white(time) or V=white(time*treq) where freq is a parameter for a mid frequency for analysis.
You may also use V=rand(time) or V=rand(time*treq). Neither such source is a good approximation for a real Gaussian, but with Box-Mueller algorithm it may be close enough.

[Qiaozhi]

I need to study the user manual of this software.
However, it was for analyse frequency response but it is correct AC analysis.
Thank you.

For the frequency domain you can use the .noise command. This allows you to compute the spectral noise density of Johnson, shot, and flicker noise per unit square-root bandwidth. The output noise is referred to an independent source. This is not a noise generator, but represents the input reference for the noise measurements. In most cases, it is the same input at that used for the .ac analysis.

[MaverickITA]

I'm still wondering what you may need white noise for. The way to make simulation noise sources more Gaussian, you may use the Box-Mueller algorithm. You need two independent random variables for it.
For a simple noise source in LTspice you may use an arbitrary behavioural voltage source, and assign voltage as a function V=white(time) or V=white(time*treq) where freq is a parameter for a mid frequency for analysis.
You may also use V=rand(time) or V=rand(time*treq). Neither such source is a good approximation for a real Gaussian, but with Box-Mueller algorithm it may be close enough.

Davor,
I did not know that there was a chance to do the analysis of frequency response.
So I thought of a white noise generator to see how responded a filter.
Yes, it is a not the correct way but it was the first thing I have thinked to go over the obstacle.

[Davor]

It may be the only way in large signal scales, power amplifiers and such, but it takes lots of time. AC analysis is much faster but is valid only for small signals. Good luck

[scrungy_doolittle]

I have tried many different ways of shielding with a space blanket and every one has failed.

cardboard plate covered in graphite works fine.


Never tried aluminum tape but if it's too thick you will loose sensitivity

Try black conductive foam like they use for shipping IC's

[MaverickITA]

Try black conductive foam like they use for shipping IC's

Your information is very interesting, I will try it as soon as possible.
Thank you