does anyone know the diffrece between noise and interference ?
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I would say the difference is how they are generated - internally is noise and externally is interference. Noise is just random electrical signals generated by an electrical/electronic system. If the noise become sufficiently large it may propagate out of the system and interfere with other electronic systems. This interference is expressed as noise in the new system so in effect they are the same thing.
Just an example.
Let's say that you have an access point somewhere. You can measure the average noise and set a threshold (your 'real' signal will be signal you receive - measures noise).
If for some reason another AP is on the area (on the same or nearby channels) they will interfere each other.
You could have a look at http://cnx.org/content/m0515/latest/
Summary : Interference is due to man-made devices while noise is due to the nature. Inteference is a "structured" signals while noise is not.