Period analysis

Let us assume that table OBSERVP.tbl contains observations of a periodic phenomenon. The observations are stored in the DOUBLE PRECISION columns :TIME and :VALUE.

 
 CREATE/GRAPHICS                   		 ! Create graphics window

 SET/CONTEXT TSA                   		 ! Enable TSA package

 NORMALIZE/TSA OBSERVP :VALUE      		 ! Subtract mean

 BAND/TSA OBSERVP                  		 ! Find suitable frequency band

 SHOW/TSA                          		 ! Inspect corresponding settings

 POWER/TSA OBSERVP POWERSPEC       		 ! Compute power spectrum and

 		 ! spectral window

 PLOT/ROW POWERSPEC                		 ! Display power spectrum

 PLOT/ROW POWERSPEC 2              		 ! Display spectral window

 AOV/TSA ? AOVSPEC ? ? ?           		 ! Compute AOV test statistics

 PLOT/ROW AOVSPEC                  		 ! Inspect results

 POWER/TSA ? LINESPEC 20 .01 501   		 ! Compute detail of power spec.

 PLOT/ROW LINESPEC                 
  ! Plot it

 WIDTH/TSA LINESPEC                		 ! Find parameters of

 		 ! the oscillation

 SINEFIT/TSA OBSERVP CLNOBS 23 1   		 ! Remove one particular

 		 ! Fourier component

 POWER/TSA CLNOBS POWCLN           		 ! Inspect periodogram of data

                           		 ! after removal of 1 oscillation