% @(#)power_tsa.hlq	10.3 (ESO-IPG) 7/9/96 09:47:21
%+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 
%.COPYRIGHT (c) 1992 European Southern Observatory & Copernicus Astron. Center%.IDENT     power_tsa.hlq
%.AUTHOR    Alex Schwarzenberg-Czerny, ESO & Copernicus Astronomical Center 
%.KEYWORD   MIDAS, help files, POWER/TSA
%.LANGUAGE  LATEX
%.PURPOSE   Compute discrete power spectrum 
%.VERSION   0.0               June 1992
%.RETURNS   None  
%.ENVIRON   TSA context
%-----------------------------------------------------------------------------
\se
SECTION./TSA
\es\co
POWER/TSA                                15-SEPT-1992 A.Schwarzenberg-Czerny
\oc\su
POWER/TSA intab outima start step nsteps
	Compute discrete power spectrum for uneven sampling by slow method
\us\pu
Purpose:  
           Compute discrete power spectrum for uneven sampling by slow method.
           This command is recommended as departure point for the analysis
           of sampling (spectral window) and signal. However, since the power
           spectrum has no well defined statistical properties we recommend
           use of AOV/TSA and/or SCARGLE/TSA for assessing the significance
           of features in the periodogrammes.
\up\sy
Syntax:
           POWER/TSA intab outima start step nsteps
\ys\pa
           intab  = name of input table, it must contain columns :TIME and 
	            :VALUE in DOUBLE PRECISION. For numerical reasons it is
                    advisable to subtract mean from :VALUE, except for window 
                    function calculation.
\ap\pa
           outtab = name of output image; its first row contains the power  
                    spectrum and second row contains the window function. 
\ap\pa 
           start  = start frequency of the periodogramme, in inverse
                    units of :TIME 
\ap\pa 
           step   = frequency step of the periodogramme, in inverse
                    units of :TIME 
\ap\pa 
           nsteps = number of frequencies of the periodogramme, in inverse
                    units of :TIME 
\ap\sa
See also:
           SHOW/TSA, AOV/TSA, SCARGLE/TSA
\as\no
Note: 
           By default 'intab', 'outtab', 'start', 'step' and  'nsteps'
           retain their values from the last use of TSA commands, unless 
           explicitly specified.
\\
           For detection of smooth signals use SCARGLE/TSA.
\\
           Sensitivity of power spectrum to signals with  sharp features is 
           poor, use AOV/TSA instead. 
\on\exs
Examples:
\ex
           POWER/TSA LCURVE PERIODG 0.01 0.01 100 
\xe\ex
           POWER/TSA ? ? 0.2 0.0001
           You may run this second command after the first example to inspect 
           the frequency range 0.2 to 0.21 at higher resolution.
\xe\sxe
