% Program P10_2% Illustration of Down-Sampling by an Integer Factor%clf;n = 0: 49;m = 0: 50*3 - 1;x = sin(2*pi*0.042*m);y = x([1 : 3 : length(x)]);subplot(2,1,1)stem(n, x(1:50)); axis([0 50 -1.2 1.2]);title('Input Sequence');xlabel('Time index n');ylabel('Amplitude');subplot(2,1,2)stem(n, y); axis([0 50 -1.2 1.2]);title('Output Sequence');ylabel('Amplitude');xlabel('Time index n');