%% ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

%%            Output Info about this m-file

fprintf('\n***********************************************************\n');

fprintf('        <DSP using MATLAB> Problem 6.5 \n\n');

banner();

%% ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

b = [1 -2.828 3.97 -2.828 1]; a = [1 -2.536 3.215 -2.054 0.6560];

fprintf('\nConvert DIRECT-form to CASCADE-form :     \n');

[b0, Bc, Ac] = dir2cas(b, a)

fprintf('\nConvert DIRECT-form to PARALLEL-form :     \n');

[C, Bp, Ap] = dir2par(b, a) 

% -----------------------------------------

%     START check

% -----------------------------------------

n = [0:7];

delta = impseq(0, 0, 7)

%format long

format  short

hcas = casfiltr(b0, Bc, Ac, delta)

hpar = parfiltr(C, Bp, Ap, delta)

hdir = filter(b, a, delta)

% -------------------------------------------

%       END check

% -------------------------------------------

figure('NumberTitle', 'off', 'Name', 'P6.5 hcas(n), hpar(n) and hdir(n)')

set(gcf,'Color','white');

subplot(3,1,1); stem(n, hcas);

xlabel('n'); ylabel('hcas(n)');

title('hcas(n)');  grid on;

subplot(3,1,2); stem(n, hpar);

xlabel('n'); ylabel('hpar(n)');

title('hpar(n)');  grid on;

subplot(3,1,3); stem(n, hdir);

xlabel('n'); ylabel('hdir(n)');

title('hdir(n)');  grid on;