Matlab de2bi function gives 0.5 as an output ? How is it possible ? How to get rid of that ?

Hi all,

I'm using de2bi function in my matlab code (16QAM communication system) to convert QAM symbols into binary number. However, when I simulate the system for large number of bits (1e8), I found that the 'de2bi' function gives '0.5' as an output. It should give only '0' or '1' as the output.

Can anyone explain this issue and how to avoid this error ?

Thanks in advance.