ex10_8.m

Programs for the book Advanced Engineering Mathematics using MATLAB, 2ndEd.

%EX10_8.M Amplitude and phase of frequency response for 
%  smoothing filter y(n) = ay(n-1)+ (1-a)x(n) 
%
clear
clf
a=[.5 .75 63/64];
F=0:.01:0.5;
[A11,phi1]=freqvals(a(1),F);
[A12,phi2]=freqvals(a(2),F);
[A13,phi3]=freqvals(a(3),F);
subplot(2,1,1),plot(F,A11,'-',F,A12,'--',F,A13,':')
xlabel('Digital frequency')
ylabel('Amplitude')
legend('a=0.5','a=0.75','a=63/64') 
subplot(2,1,2),plot(F,phi1,'-',F,phi2,'--',F,phi3,':')
axis([0 .5 -90 0])
ylabel('Phase, degrees')
legend('a=0.5','a=0.75','a=63/64') 
%hold on
%subplot(2,1,1),plot(F,A12)
%subplot(2,1,2),plot(F,phi2)
%subplot(2,1,1),plot(F,A13)
%subplot(2,1,2),plot(F,phi3)
%