; This batch file creates a plot of the power spectrum of 
; the simulated signal used in the example from Chapter 13,
; "Signal Processing", of _Using IDL_, with a 30 cycle/second
; periodic component added.

N = 1024                      ; number of time samples in data set

delt = 0.02                   ; sampling interval in seconds

T = delt * FINDGEN(N)         ; vector of discrete times

f1 = 5.0 / ((n-1)*delt)

f2 = 0.5 / ((n-1)*delt)

R = SIN(2*!PI*f1*T) * SIN(2*!PI*f2*T)
 
PLOT_3DBOX, T, R, -FLOAT(HILBERT(R)), $
    AX=40, AZ=15, XTICKS=5, XCHARSIZE=2, XTITLE = 'time in seconds', $
    YTICKS=2, YCHARSIZE=2, YTITLE = 'real', YMARGIN=[4,8], $
    ZTICKS=2, ZCHARSIZE=2, ZTITLE = 'imaginary'

XYOUTS, 0.5, 0.95, /NORMAL, ALIGNMENT=0.5, SIZE=1.5, $
    'Analytic Signal for r(t) Using Hilbert Transform'