;  $Id: //depot/idl/IDL_71/idldir/examples/doc/signal/sigprc03#1 $

;  Copyright (c) 2005-2009, ITT Visual Information Solutions. All
;       rights reserved.
; 
; This batch file creates a plot of the real and imaginary parts
; of a simulated signal.

; Compute time sequence data:
@sigprc01
; Compute spectrum v:
V = FFT(U)
M = (INDGEN(N)-(N/2-1))
; Frequencies corresponding to m in cycles/second:
F = M / (N*delt)
; Set up for two plots in window:
IPLOT, F, FLOAT(SHIFT(V,N/2-1)), $
   DIMENSIONS=[500,800], VIEW_GRID=[1,2], $
   YTITLE='Real part of spectrum', $
   XTITLE='Frequency in cycles / second', $
   XRANGE=[-1,1]/(2*delt), $
   TITLE='Real and Imaginary Spectrum of u(k)'

IPLOT, F, IMAGINARY(SHIFT(V,N/2-1)), $
   /VIEW_NEXT, $
   YTITLE='Imaginary part of spectrum', $
   XTITLE='Frequency in cycles / second', $
   XRANGE=[-1,1]/(2*delt)

