can someone please explain to me how this works. I think it is a LCCDE filter.

n = 1;
m = 1:900;
C = wavread('ecg1.wav');
X = wavread('ecg2.wav');
for B = .4 : .1 : 1;
b = [1 -B 1];
a = [1 0 0];
y = filter(b,a,X);

[Walter Roberson]

part of the loop is missing, and it is important for understanding the purpose of the code.