20 30 10 20 30 x[]=cos20k,g20=0 x[]=cos20k,g20=0.2兀 10 20 30 10 20 30 x[]=cos0k,20=0.87 x[]=cos2ok,g20=兀8 0 10 20 30 40 -1 0 1 x[k] = cos0 k , 0=0.2p 0 10 20 30 40 -1 0 1 x[k] = cos0 k , 0=0.8p 0 10 20 30 40 -1 0 1 x[k] = cos0 k , 0 =p 0 10 20 30 40 -1 0 1 x[k] = cos0 k , 0=0