newf.m

It a filter. Buterwarth filter. very important tool in gsm

fc=25;
fs=100;
t=[0:1/fs:2];
x= sawtooth(6*t,0);
y=amod(x,fc,fs,'amssb');
f=fc/fs;
[num,den]=butter(2,f);
z=ademod(y,fc,fs,'amssb',num,den);
plot (t,x,'-',t,z,'--');