Generating noise with constant RMS

rms constrant

I would like to generate noise from 100Hz to 1kHz. Its spectral components should be falling with higher frequencies similar as in the picture (it would be desirable, that I can adnjust the frequency slope). The noise should have constant RMS value.

In the current circuit I take white noise from function generator and limit it to frequencies 100-1000Hz. Then I amplify this signal and put it though a filter which define the frequency slope of the noise (one of the versions is in the attachment).

With this method I get noise with desired spectral components.
The problem is, that the RMS value of the noise is not constant, but it is changing for about +/-5% in time base of minutes.

Is it possible to generate such a noise with function generator + analog circuit, or should I try to generate it with matlab and then use a DAC?

rms white noise generate

The noise should have constant RMS value.

Click to expand...

It can't be exactly constant. Depending on the intended measuring time, you may want to use a shorter pseudo random sequence for the input "white" noise.

noise rms sec to noise min

FvM said:

The noise should have constant RMS value.

Click to expand...

It can't be exactly constant. Depending on the intended measuring time, you may want to use a shorter pseudo random sequence for the input "white" noise.

Click to expand...

Thank you for the answer.
This could be a solution as I can average for a few seconds the measured noise.
So to get a constant value from the rms meter I need to use a pseudo random sequence of a few seconds.