Power penalty

[Leeba BabuParticipant]

I need to plot BER as a function of received power to find power penalty. Is there any range for power that is to be plotted in order to find power penalty?

[alistuParticipant]

Hi Leeba,

I suggest that you use sweep mode for a wide range of power change (say 30dB). Then you can choose a smaller range which gives results of more interest. It really depends on your system.

Regards

[Alessandro FestaParticipant]

The power penalty depends on many factors (bitrate, modulation type…) so it depends on your system. If for example you have a simple tx -> fiber -> receiver system, you can simply add a VOA in front of the receiver and the change its attenuation from 0dB to xx dB to see how BER changes.

[Leeba BabuParticipant]

Thanks alistu and alessandro for your reply.. let me try it out

[Alessandro FestaParticipant]

You are welcome Leeba!

[Leeba BabuParticipant]

Why in some cases BER is plotted against received power while log of BER is plotted against received power in other cases? Is there any relation between the two plots ?

[alistuParticipant]

Almost all cases I can remember now have used the log of BER, even though it might also be shown otherwise as you have mentioned. Using log of BER, the changes in a rather small interval (say from zero to one, the BER range) as well as changes in a wide range can be shown better and more clearly.