Communications Toolbox

Computing and Displaying Bit Error Rates

The biterr function compares each demodulated signal (that is, each column of newsignal) to the original signal. Then biterr computes the number of bit errors, as well as the rate or fraction of bit errors. The built-in MATLAB function disp displays the two bit error rates in the MATLAB Command Window.

• % Check whether Gray code resulted in fewer bit errors.
  % Compare signal with each column of newsignal.
  [num,rate] = biterr(newsignal,signal); 
  disp('Bit error rates for the two constellations used here')
  disp('----------------------------------------------------')
  disp(['Gray code constellation:     ', num2str(rate(1))])
  disp(['Non-Gray code constellation: ', num2str(rate(2))])
  

Demodulating the Signal

Plotting a Signal Constellation