Of course, noise is more significant the higher in frequency. I’m not sure 200MHz really covers the important range. At lower frequencies, noise is more significant than what even a tube generates.

Look for the Hearing icon, and long-press it to bring up the following menu: Toggle white noise on and off from the iPhone’s Control Center. Image source: Chris Smith, BGR ...

White noise is very useful in testing many types of circuits. When combined with an FFT analyzer, a flat noise source can make for quick and easy gain plots of circuits. If the noise into a circuit is ...

The noise source should also be useful for measuring the gain characteristics of low-level preamplifiers, but you’ll likely need to reduce the RF output by at least 40 dB with an attenuator, so the ...