MatLab Solutions: "Introduction to Digital Signal Processing: A Computer Laboratory Textbook".
29 Oct 2012
25 Nov 2013)
These files are the MatLab solutions of exercises contained in the above DSP lab textbook.
% Linear Convolution calculated via the Discrete Hartley Transform (DHT).
% Warning: It is good for convolution calculation of real input sequences only.
function z = conv_DHT(x,y)
% Make sure x and h are row vectors.
x = x(:).';
y = y(:).';
N = length(x);
M = length(y);
L = 2^nextpow2(N+M-1);
x1 = [x zeros(1,L-N)]; % Zero-pad as required to make the length
y1 = [y zeros(1,L-M)]; % of both sequences equal to L=2^n for max fft() performance.
% Calculate the DHT of h1[n] and x1:
X = my_DHT(x1);
Y = my_DHT(y1);
% Next calulate the even and odd parts of H:
Yeven = (Y + circshift(fliplr(Y),[0 1]))/2;
Yodd = (Y - circshift(fliplr(Y),[0 1]))/2;
%Calculate the DHT of the output using the given formula:
Z = X.*Yeven + circshift(fliplr(X),[0 1]).*Yodd;
z = 1/L*my_DHT(Z);
% Now keep only the valid samples:
z = z(1:N+M-1);