|Date: ||Mon, 12 Oct 1998 12:55:03 -0400|
|Reply-To: ||Puhong Gao <pgao@BROADWAY.GC.CUNY.EDU>|
|Sender: ||"SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>|
|From: ||Puhong Gao <pgao@BROADWAY.GC.CUNY.EDU>|
|Subject: ||Fourier transforms with SAS?|
|Content-Type: ||text/plain; charset=us-ascii|
Hi, SAS gurus,
I am studying the rat's whisking behavior and need to analyze my data by
using Fourier transformation. During exploration or discrimination, a
rat moves its whiskers back and forth, in a range of 1 to 25 Hz (mainly
6-9 Hz). My data are the serial positions of a monitored whisker (a data
point every 1.4 ms). If I plot my data against time, they will be in a
sine wavelike form. I need to use fourier analysis to transform my data
into a distribution of spectral densities. I know a little about SAS.
Seems to me that PROC SPECTA may do the job. After tried with PROC
SPECTRA, I don't understand why the returned frequency values are always
set from 0 to 3.14159 (PI). Any suggestion will be highly appreciated.
Thanks. Also, are there any good books for time series analysis?