Re: Channel

Almas_Uddin_Ahmed wrote:

if noise we consider awgn that has zero mean and varince . how much
variance is occured when our signal (0/1 ) i study by using pdf to find
out probability of the random variable and intregated to pdf to find
probabilty distribution that means area of the random variable.

i m not clear how i can find out variance? i understand varince in
terms of statistics example but when i study in communication i can't
able to fix up this problem.

noise are consider normal, gaussian and probability distribution all
they r same?

m i right? by using pdf to find out a random varible and using
intregated of pdf to find out how much spreading random varible from
one point to anothe point so those one point use for mean and anothe
point use for varince?

First -- You're posting from Google, and you obviously haven't read (or at least haven't heeded) the directions in the link referenced below. Please read it. Particularly the part about how USENET isn't a web-based forum, and it's up to you to provide context.

Second -- you're abbreviating just a bit too much. I _think_ when you say "signal (0/1 )" you mean a zero-mean normally distributed variable with variance = 1? Yes? No? Your notation leaves too much out.

You find the variance by turning your communications problems into statistics problems. Statistics deal with random processes, just like communications does. Variance in a signal is the same as variance in a random variable.

A variable with a normal distribution is Gaussian. The probability distribution of a random variable (or process) _can_ be Gaussian, but isn't _necessarily_ Gaussian -- this is basic statistics which you can review.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google? See http://cfaj.freeshell.org/google/
.

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