# Earthworm Module:
Ewspectra Overview

(last revised 26 April, 2011)

The ewspectra module takes data from one or more waveservers, can perform a variety of operations on that data, most importantly computing an FFT and identifying the frequencies w/ the highest amplitudes in the resulting spectra. Results can be written to files in a specified directory or as messages to a ring. Specification of the timespans to process can be specified in the configuration file and/or via messages read from a ring.

The primary option is what SCNLs to monitor and, if 2 are specified, how to combine them:

- A single SCNL is specified & its spectra computed
- 2 SCNLs are specified and the difference between their spectra is computed
- 2 SCNLs are specified, and their spectra are deconvolved

Other options include tapering of the original timeseries, applying high- and/or low-pass Butterworth filters, and smoothing the spectra before writing.

Module Index | ewspectra Configuration File