Forums

Generate Gaussian Noise

Started by sharma rohit December 7, 2004
Hi! Folks
I know that randn would generate a set Gaussian samples. But if I need to add gaussian noise to my signal such that the noise power is some value N, how do I do it?
How would the variance (that I would give to my rand function)  var vary as N?
Please explain?
 
Your help is appreciated!!!

Regards
Rohit Sharma


Rohit Sharma,
65,Villages at North Gate,
3000, July Street
Baton Rouge,
LA, 70803
USA.
"We met as total strangers and ended as lifetime friends, we shared a season of our lives, but every season has to end."




Hi,
Multiply by sqrt(N) to the ranom smaples u
generated.
I mean sqrt(N)*randn will generate a random noise with
desied variance of N.
HTH,
-SaiRamesh.
--- sharma rohit <> wrote:

> Hi! Folks
> I know that randn would generate a set Gaussian
> samples. But if I need to add gaussian noise to my
> signal such that the noise power is some value N,
> how do I do it?
> How would the variance (that I would give to my rand
> function) var vary as N?
> Please explain?
>
> Your help is appreciated!!!
>
> Regards
> Rohit Sharma > Rohit Sharma,
> 65,Villages at North Gate,
> 3000, July Street
> Baton Rouge,
> LA, 70803
> USA.
> "We met as total strangers and ended as lifetime
> friends, we shared a season of our lives, but every
> season has to end."
>
> ---------------------------------
>
__________________________________




Hi,
I think what you are looking for here is rms power. Therefore you
will have:

normalized_noise=noise/std(noise,1);
noise_power = reqdpower*normalized_noise;

Generally you dont find the power of the entire segment all at once,
but since this is gaussian noise, it should not really matter.

Mandar --- nammi sairamesh <> wrote:

>
> Hi,
> Multiply by sqrt(N) to the ranom smaples u
> generated.
> I mean sqrt(N)*randn will generate a random noise with
> desied variance of N.
> HTH,
> -SaiRamesh.
> --- sharma rohit <> wrote:
>
> > Hi! Folks
> > I know that randn would generate a set Gaussian
> > samples. But if I need to add gaussian noise to my
> > signal such that the noise power is some value N,
> > how do I do it?
> > How would the variance (that I would give to my rand
> > function) var vary as N?
> > Please explain?
> >
> > Your help is appreciated!!!
> >
> > Regards
> > Rohit Sharma
> >
> >
> > Rohit Sharma,
> > 65,Villages at North Gate,
> > 3000, July Street
> > Baton Rouge,
> > LA, 70803
> > USA.
> > "We met as total strangers and ended as lifetime
> > friends, we shared a season of our lives, but every
> > season has to end."
> >
> > ---------------------------------
> >