External noise generation with Matlab

Hi

Do you if there is a toolbox or function to generate noise which is
received after a RF transmission (a model of external noise with man-made
noise, galactic noise, noise due to attenuation and noise due to lightning
discharges)?

Thank you

"thom" <soniceric@hotmail.com> wrote in message 
news:hd2dnZOmbbF7ZsTZnZ2dnUVZ_vqdnZ2d@giganews.com...
> Hi
>
> Do you if there is a toolbox or function to generate noise which is
> received after a RF transmission (a model of external noise with man-made
> noise, galactic noise, noise due to attenuation and noise due to lightning
> discharges)?
>
> Thank you

"wgn" perhaps?

I'm not familiar with "noise due to attenuation" - maybe you can explain 
what that is....

fred 

>"wgn" perhaps?
>
>I'm not familiar with "noise due to attenuation" - maybe you can explain

>what that is....
>
>fred 


Well, we often model noise received after a wireless transmission by
Additive White Gaussian Noise. Actually in the HF band noise from electric
discharge in the atmosphere is dominant; then for frequencies between 20Mhz
to 1GHz, it is noise from space (galactic noise); for frequency up to 1GHz
thermal noise due to atmospheric attenuation is the dominant noise source.
You can add noise due to human activity.

I would like to model this noise, not only with White Noise if it's
possible. Maybe someone knows if it is??

>Hi
>
>Do you if there is a toolbox or function to generate noise which is
>received after a RF transmission (a model of external noise with
man-made
>noise, galactic noise, noise due to attenuation and noise due to
lightning
>discharges)?
>
>Thank you
>

Do you want to model the noise or generate a RF noise? In both cases I
would first generate a pseudo random complex waveform in baseband for the
desired noise according to its stochastic characteristics. If the latter
is known it's not difficult to program by e.g. Matlab, C or C++. Then the
waveform can be loaded into a general purpose signal generator and
modulated to the band of interest. That's it.

>Do you want to model the noise or generate a RF noise? In both cases I
>would first generate a pseudo random complex waveform in baseband for
the
>desired noise according to its stochastic characteristics. If the latter
>is known it's not difficult to program by e.g. Matlab, C or C++. Then
the
>waveform can be loaded into a general purpose signal generator and
>modulated to the band of interest. That's it.
>


I would like to generate a noise with Matlab which could look like noise
that an antenna receives (not only a white gaussian noise which is an
approximation). Then this noise will be added to a signal, to simulate
noise reduction methods.

How about design a filter that has the same PSD as your noise and then
use that filter on a AWGN sequence?

thom wrote:

   ...

>                          ... for frequencies between 20Mhz
> to 1GHz, it is noise from space (galactic noise) ...

You never spent much time on the 10- and 6-meter ham bands, or tuned to 
an unused television channel.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������