y3k=fft(u,(m+n-2)/4)



i=1:(m+n-2)/4

subplot(5,2,9) stem(i,u)

title( 滤波后上采样 )



k=1:(m+n-2)/4

subplot(5,2,10) stem(k,y3k)

title( 上采样频谱 )

xlabel( k ) ylabel( y3k ) -y3k = fft (u, (m+ n-2)/4) i = 1: (m+ n-2)/4 subplot (5,2,9) stem (i, u) title (after filtering the sample) k = 1: (m+ n-2)/4 subplot (5,2,10) stem (k, y3k) title (on the sample spectrum) xlabel (k) ylabel (y3k)