finished exercise except for some parts of number 1

Assignment2_211/assignment2_4.m

@@ -0,0 +1,29 @@
+function X = dtft ( x , n , w )
+    % DTFT Computes Discrete-time Fourier transform
+    % @param x : finite duration sequence (vector) over n
+    % @param n : sample indices vector
+    % @param w : frequency vector
+    % @return X : DTFT of x[n] at frequencies w
+    % this function does not use for loops
+    X = sum(x(:) .* exp(-1j * n(:) * w), 1);
+end
+
+n = -10:10;
+x = (0.8) .^ abs(n) .* ((n >= -10) & (n < 11));
+w = linspace(-pi, pi, 1000);
+
+X = dtft(x, n, w);
+
+magnitude = abs(X);
+phase = angle(X);
+figure;
+subplot(2, 1, 1);
+plot(w, magnitude);
+title('Magnitude Response');
+xlabel('Frequency (rad/sample)');
+ylabel('|X(w)|');
+subplot(2, 1, 2);
+plot(w, phase);
+title('Phase Response');
+xlabel('Frequency (rad/sample)');
+ylabel('Phase(rad)');