fm=20000 and I am sampling following signal at 65000 Hz:
x=0.5*sin(2*pi*(fm-2500)*t)+0.6*sin(2*pi*(fm-1250)*t*1.05)+0.7*sin(2*pi*fm*t*1.1)+0.8*sin(2*pi*(fm+1250)*t*1.15)+0.9*sin(2*pi*(fm+2500)*t*1.2);
and looking at frequency spectrum is not as it should look like.
Please find attachment.
It has code and result also.