Data rollers; e1 = (1/.6)*normal(123); 
  Do t = 1 to 1000; e=.8*e1+ normal(123); aligned = 10 + .05* normal(123); 
  cycle= 10+ .01*sin(8*atan(1)*t/25); 
  thickness = round (aligned + cycle-10,.002); 
  output; e1=e; end; 
  proc gplot; plot (thickness cycle)*t/overlay; 
  symbol1 v=none i=join c=black; 
  symbol2 v=dot h=.7 i=join c=gray; 
  proc gchart; vbar thickness; 
  proc univariate normal plot; var thickness; 
  proc spectra data= rollers p s adjmean out=out1; Var thickness aligned; 
  weights 1 1 1 1 1 1 1 20 1 1 1 1 1 1 1; 
  proc gplot; plot P_01*freq/href =  .5  1 1.5 2 2.5 3; 
  symbol1 v=diamond i=needle c=black; 
  proc print data=out1; where .2 < freq<.3; 
  run;