Calculating BER for optical communications

Hi!

I would like to calculate the BER of an optical communications
system.

The only known value is the total collected intensity as a function of
time (I thus can calculate mean intensity, variance,...). The
modulation format doesn't matter. The simplest is the best; so we can
take OOK modulation. I think that BER is also function of the SNR.

How can I calculated the BER if I take a OOK modulation (or any other)
and fix the SNR to a certain value?

Thank you for your time,
Noah

noahh.schwartz@gmail.com wrote:
> Hi!
> 
> I would like to calculate the BER of an optical communications
> system.
> 
> The only known value is the total collected intensity as a function of
> time (I thus can calculate mean intensity, variance,...). The
> modulation format doesn't matter. The simplest is the best; so we can
> take OOK modulation. I think that BER is also function of the SNR.
> 
> How can I calculated the BER if I take a OOK modulation (or any other)
> and fix the SNR to a certain value?
> 
> Thank you for your time,
> Noah

Have you done a web search for "BER calculation?"

In broad terms, you find the probability distribution of your received 
signal when a zero has been transmitted, and the probability 
distribution of your received signal when a one has been transmitted. 
Then you use these PDFs along with the receiver design to calculate the 
fraction of bits received in error.

Doing this calculation requires that you know the SNR of your received 
signal at your receiver's bit slicer, which usually requires you to know 
the SNR of the signal going into your detector as well as the physics of 
your detector (or at least its behavior in detail) and any signal 
processing hardware that follows it.

-- 

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

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html