How can I generate a noise with a required sensitivily power ? i.e. -174 dBm

DEAR ALL:

Iwant to simulate a RF system, the question is how can I generate a noise with a required sensitivily power ? i.e. -174 dBm. Please help me, thanks

Answer 1

[Paul]

See http://www.mathworks.com/help/comm/ref/awgn.html or http://www.mathworks.com/help/comm/ref/wgn.html

Answer 2

[Iain]

First: calculate the power value.

-174dBm, is 17.4 orders of magnitude down from "milli", so

 noise_RMS = 0.001 * 10^-17.4;

Calculate a random signal of "x" elements:

 random = randn(x,1);

Scale it to the right "rms"

 noise_RMS*power