DSP Lab Experiments - Digital Signal Processing: An Introduction with MATLAB and Applications - page 338

10 0

10 −1

10 −2

10 −3

10 −4

10 −5

0 2 4 6 8 10 12

SNR , dB

Fig. D.11 Probability of error versus SNR in baseband binary communications

function. This is important in many applications like communications between
computers operating in the same neighborhood.

Task 1

Simulate a binary communication system with two orthogonal signals. Use the
flowchart shown in Fig. D.13 . Take E = 1 and generate N = 1000 bits data
sequence {d(n)}. To generate a sequence of equiprobable 1's and 0's, use ''rand''
function on MATLAB, which gives you a random number uniformly distributed
over the interval (0,1). Use the simple rule: if rand [0.5, then d(n) is ''1'',
otherwise ''0''. However, you should use a smart algorithm for data generation that
avoids the use of loops. Mix data with noise to simulate transmission and matched
filter reception, then find the probability of error as a function of the SNR. Better to
use a separate function for the probability of error calculation. Compare with the
theoretical curve.

s o ( t )

Fig. D.12 Two antipodal signals

1

t

T

− 1

T/2

s 1 ( t )

1

T

t

− 1

T/2