I need to understand how to use the White Noise block in Simulink.

I am trying to use the White Noise block in Simulink. It has a few parameters, such as "Noise Power" and "Seed". I don't know what these mean. I want to produce a white noise result that varies between 0 and 300 m/s to simulate a variable wind/turbulence source. If the white noise source produces values from 0 to 1 I can clearly multiply that by 300 to produce a result. (I don't know that it is producing values from 0 to 1.) The problem is that I don't know how to translate "Noise Power" into something with meaning for me. The "Seed" value seems less important. It appears to have a default value of [23341]. The "Noise Power" has a default value of [0.1]. I don't understand what the "Noise Power" value means or how to use it to translate it into behavior relative to variable wind speed/turbulence. Can someone please translate meaningfully? Please don't use advanced math, or I probably won't grasp the response.

Answer 1

[Jack]

Noise Power

– Think of Noise Power as how “big” the random wiggles are. A higher value makes larger swings. In Simulink’s White Noise block, Noise Power really means the variance of a zero-mean Gaussian signal. In everyday terms:

• Noise Power = 1 gives you noise that usually stays within about ±1.
• Noise Power = 0.1 (the default) gives you noise that usually stays within about ±0.3 (since √0.1≈0.32).

Seed

– The Seed just picks the starting point for the random sequence. If you leave it at 23341 you’ll get the same pattern every run; change it (or randomize it) for a new noise pattern.

Getting “Wind” Between 0 and 300 m/s

1. Center & Scale:The White Noise block produces values centered at 0. To swing around a mean of 150 m/s with typical amplitude ±150 m/s, set Noise Power = 1, then use a Gain and Bias:

• Gain = 150
• Bias = 150
• That gives mostly 0→300 m/s (with occasional small overshoots).

1. Strict 0–300 Range:White noise is Gaussian (unbounded), so if you need values strictly between 0 and 300, use the Random Number block instead. Set its

• Minimum = 0
• Maximum = 300
• –– and it will give you a uniform random value in that range each sample.

Quick Steps for White Noise + Scaling

1. Drop in the White Noise block.
2. Set Noise Power = 1.
3. Add a Gain block (Gain = 150).
4. Add a Bias block (Bias = 150).
5. Your signal now wiggles around 150 m/s with typical swing ±150 m/s.

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