algorithmic difference between random number generator and band-limited white noise

The band-limite white noise mentions "The primary difference between this block and the Random Number block is that the Band-Limited White Noise block produces output at a specific sample rate. This rate is related to the correlation time of the noise."

1) The random number generator block also geenrates noise at specific rate only. Whta does this sentence trying to decipher?

2) The band limited white noise has the following algo underneath it is shown below

where K = sqrt(Cov)/srt(Ts).

So apart from just power tuning, the band limit white noise does not control the correlation? Please explain me the difference here.

Answer 1

[Aabha]

Hi @Devyani Varshney,

There is a difference in the functionalities of the two blocks mentioned. The ‘Random Number block’ generates independent samples at each time step. This means each value is uncorrelated with the previous one and as a result, the noise is white in time. For example, if you sampled it at 1 kHz, you would get independent random values after every 1 ms, and the correlation time is essentially zero.

However, the sample rate for the ‘Band Limited White Noise’ block is related to how smooth or correlated the noise is i.e., its correlation time. The block adds temporal correlation by limiting the noise’s frequency content. This is more realistic for physical systems, where high-frequency components are filtered out.

Please refer to the following documentation links for more information about the blocks: https://www.mathworks.com/help/releases/r2023b/simulink/slref/randomnumber.html https://www.mathworks.com/help/releases/r2023b/simulink/slref/bandlimitedwhitenoise.html

I hope this answers your question.