Generate a random signal with varying frequencies and constant rms

Hi

I am busy doing a project regarding the ISO 2631-1 filters that you apply to accelerometer data to evaluate human comfort. I am done with the filter design and is testing it at the moment.

I want to generate a random signal, x (time) and y (acceleration), where the signal has an RMS of 1, but the frequency of the signal varies. So I am currently extracting the dominant frequencies from my FFT data, so I want multiple frequencies to extract from the FFT. The frequencies of the signal should range between 0.1 Hz and 80 Hz.

Can anayone help please

Answer 1

[Garv Agarwal]

Hi Daniel,

From my understanding, you want to generate a random signal with varying frequncy but constant rms value.

For generation the random frequencies, you can use the rand function-

r = minVal + (maxVal-minVal)*rand(sampleSize)

Then you can use these frequencies to create a sine wave.

The signal generated will then have to be normalized to have rms value of 1. You can do this by dividing the signal by its own rms value -

signal = signal/rms(signal)

You can read more about these functions, from the following documentations -

https://in.mathworks.com/help/matlab/ref/rand.html

https://in.mathworks.com/help/matlab/ref/rms.html