generate white gaussian noise

I want to generate a white gaussian noise vector by following the example given in Mathwork website:

y1=wgn(1000,1,0);

However, I always obtained the following message:

'wgn' requires Communications Toolbox.

When I clicked Comminications Toolbox, it shows the page with the above example. What is the problem?

Thanks for any helps.

[KSSV]

Try:

which wgn

/MATLAB/toolbox/comm/comm/wgn.m

It seems, you don't have the communications toolbox.

[Hong Lin]

Is Communications toolbox an optional part of Matlab?

Answer 1

[David Goodmanson]

Hi HL,

Since white gaussian noise is just random draws from a normal distribution, you don't really need some toolbox or other, you can make your own (different example from yours):

P = 1e-3;  % power in watts assuming x is the voltage across a 1 ohm resistor
x = sqrt(P)*randn(1,10000);
format short g
rms(x-mean(x))^2
  ans =  0.0010206   % close to 1e-3

[Hong Lin]

Thank you.