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

%%            Output Info about this m-file

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

fprintf('        <DSP using MATLAB> Problem 6.9 \n\n');

banner();

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

Klr = [-0.56  2/3  1/2];

Clr = [ 0  0  0  1]; 

%format rat;

format short;

fprintf('\nConvert Lattice-Ladder-form to Direct-form :     \n');

[b, a] = ladr2dir(Klr, Clr)

fprintf('\nConvert matlab Lattice-Ladder-form to Direct-form :   \n');

[NUM, DEN] = latc2tf(Klr, Clr)

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

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

%C = 0;

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

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

fprintf('\nConvert TF-form to SOS-form :     \n');

[sos, g] = tf2sos(b, a)

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

[Klr, Clr] = dir2ladr(b, a) 

fprintf('\nConvert DIRECT-form to MATLAB LATTICE-LADDER-form :     \n');

[K, V] = tf2latc(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)

hladr = ladrfilt(Klr, Clr, delta)

hdir = filter(b, a, delta)

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

%       END check

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

figure('NumberTitle', 'off', 'Name', 'P6.9 hcas(n), hpar(n)')

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

subplot(2,1,1); stem(n, hcas);

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

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

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

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

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

figure('NumberTitle', 'off', 'Name', 'P6.9 hladr(n) hdir(n)')

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

subplot(2,1,1); stem(n, hladr);

xlabel('n'); ylabel('hladr(n)');

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

subplot(2,1,2); stem(n, hdir);

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

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