Integer and a half periods of sine wave in DFT window
That's not true. Take a simple example:


N = 8; n = 0:N-1;
w1 = pi/4; w2 = 3*pi/8;
s1 = sin(n*w1); s2 = sin(n*w2);
S1 = fft(s1); S2 = fft(s2);
subplot(2,2,1),stem(n,s1)
subplot(2,2,2), stem(n,s2)
subplot(2,2,3), stem(n,abs(S1))
subplot(2,2,4), stem(n,abs(S2))