INQUA Sub-Commission on Data-Handling Methods

Newsletter 17: February 1998

Short notes: 5 SPECTRUM news

However, Michael has now released an updated version (2.1), differing from the previous version in the following respects:

Screen Dump Option

Probably the most important change regards the output: All graphic screens can now be dumped into bitmap files (PCX format). These files can be imported into a variety of graphic programs and word processors (I checked WordPerfect 6.1, Corel Draw 5 and Corel Photo Paint 5.0 under Windows).

If you want to save a screen image, simply press the F2-key while the graphic screen is displayed.

For the sake of simplicity, the bitmap files are saved as SPEC##.PCX to the same directory were SPECTRUM.EXE is located; "##" is the actual file number that starts with 1 each time SPECTRUM is launched. Old PCX-files are over- written without any warning!!! Hence, you should move the PCX-files that you might want to use later to some other directory or simply rename them. In order to guide your bookkeeping, the actual filename (e.g., SPEC21.PCX) is displayed when the PCX-file is saved.

Note: When you are integrating the area under a spectrum of estimating the alignment time from a phase spectrum you can not produce PCX-files _after_ selecting the first and _before_ selecting the second margin!

Although the PCX-format is widely supported, I would like to recommend that you use the GNUPLOT program (vector based) for producing high quality graphics. If you have problems getting started with GNUPLOT, I can make a copy of my program setup available via ftp -- just let me know.

Less Memory required

You need only 430 kB of free conventional memory to run SPECTRUM 2.1 (560 kB in the old program version). At the same time SPECTRUM can handle larger data files: the maximum length of a time series is now 3000 data points.

(Note: SPECTRUM still requires about 1MB EMS memory.)

This reduced memory requirement allows you to run SPECTRUM in a DOS box under WINDOWS. With the "Soft WINDOWS" emulator by "INSIGNIA" you can even use SPECTRUM on UNIX and PowerMac platforms.

This larger memory efficiency was achieved by defining all variables in SINGLE PRECISION (4 Bytes) instead of DOUBLE PRECISION (8 Bytes). I don't think that this modification will _significantly_ alter any results. For those of you who want to check this out, I will keep the old version of SPECTRUM on the ftp-server (spec20b.zip). Please, let me know if you encounter any unforseen differences in the results between the two program versions.

Misc. Changes:

• display "read only" files in file selection menu
• do not halt program in case of low memory -> you can still use the univariate module
• bugfix: negative alignment times were erroneously set to zero
• bugfix: saving gnuplot scripts to the root directory is now possible (e.g., D:\mywork.plt)

Note that the documentation (SPEC20D.ZIP) has not (yet?) been updated for the above changes.

This note is based on an e-mail message circulated to SPECTRUM users by Michael Schulz. He can be contacted at:

Michael Schulz
University of Kiel
SFB 313
Heinrich-Hecht-Platz 10
D-24118 Kiel
Germany

Email: mschulz@sfb313.uni-kiel.de
Phone: +49-431-880-7324
FAX : +49-431-880-1569

Reference

Schulz, M. & Statteger, K. 1997. SPECTRUM: A PC-program for spectral analysis of unevenly spaced time series. INQUA Sub-Commission on Data-Handling Methods Newsletter 16: July 1997.

Copyright © 1998 K.D. Bennett