frit.m

qam的matlab程序。m文件

%frit.m
%fse frequency response interpretation test
%crj jr, 7/01

clear

%channel specification
d=[1,0.8,1.665,1.8095,1.11207,1.0643,0.368,0.1696,...
			     0.0452,0.0127,0.001,0.0002]';

%equalizer specification
g=[1.1447,-0.8351,-0.9231,0.9773,0.4694,-0.5467]';

%channel-equalizer baud-spaced combination
fce=conv(d,g);

%odd and even downsampled channel-equalizer combinations
oce=fce(2:2:length(fce));
ece=fce(1:2:length(fce));

%frequency responses
[dfr,wdfr]=freqz(d,1,512,'whole');
[gfr,wgfr]=freqz(g,1,512,'whole');
[ocefr,wocefr]=freqz(oce,1,256,'whole');
[ecefr,wecefr]=freqz(ece,1,256,'whole');

%check on magnitudes of odd and even frequency...
			 response interpretation formulas
checkodd=abs(ocefr)-abs(0.5*(dfr(1:256).*gfr(1:256)...
                           -dfr(257:512).*gfr(257:512)));
checkeven=abs(ecefr)-abs(0.5*(dfr(1:256).*gfr(1:256)...
			   +dfr(257:512).*gfr(257:512)));

figure(10)
clf
plot(checkodd)
title('check on odd frequency response magnitude')

figure(11)
clf
plot(checkeven)
title('check on even frequency response magnitude')