I have some confusion about practical aspects of dealing with white noise.
Let's say you want to quantify or view the white noise component of a power supply output or a constant transducer output. How is the white noise component be extracted from a measured signal in practice? Such a measurement can be done by a scope or data acquisition sampling.
But white noise power spectral is constant over infinite frequency. But how can such a signal as white noise be sampled then? If it has infinite bandwidth what should be the minimum sampling frequency when sampling white noise? Or it doesn't matter?
I know the sampling theorem but this white noise is hard to grasp when it comes to practice. Again an example would help. Let's start we have a 9V power supply and we have access to its terminals. One can see the switching noise from the FFT of the logged output signal as long as sampled at least twice the switching noise or more ect. But suppose one wants to verify the white noise component, what could be done in practice?