MATLAB: Converting 0 to -1, not working in function

Question

Hello,

I am working on a simple indexing problem where I have an array of random binary data. I simply want to convert the 0's to -1's and I am using the following code to do that:

if true
  bpsk = signal;
  bpsk( signal==0 )= -1;
end

where signal is my binary data. So this works fine in the command window but when I stick this code into a function bpsk is all 1's after the indexing. Any thoughts?

Thanks, Micah

Answer 1

signal = rand(1,10)>0.5
signal(signal==0) = -1

If signal is a logical, it can ONLY have values of 0 or 1, so anything that is nonzero will be 1. Perhaps you want to convert signal to double first?

signal = rand(1,10)>0.5
signal = double(signal)
signal(signal==0) = -1