pro fft_data,trange = tr,vname=v,window=wind $
   ,color=col,lim=lim,overplot=overplot $
   ,npoints=np

sel_data,t,y,trange=tr,vname=v,npoints=np

if not keyword_set(wind) then wind=[1.,1.]

c= n_elements(t)

if not keyword_set(lim) then lim={xlog:1,ylog:1}

if c ne 0 then begin
   w = interp(wind,c)
   print ,'Using ',c,' Points in the fft of ',v(0)
   fy = abs(fft(y*w))^2
   dt = t(c-1)-t(0)
   fx = findgen(c)/dt
   fx = fx(0:c/2)
   fy = fy(0:c/2)
   if not keyword_set(overplot) then box,lim,fx,fy
   extract_tags,oplotstuff,lim,/oplot
   add_str_element,oplotstuff,'color',col
   oplot,fx,fy,_extra = oplotstuff
;stop
endif

overplot=1

end