OCTAVE PseudoTime.m - Conversion of recorded SASW spectra to time domain pseudo signals.
PseudoTime prompts for type scaling of plot
GUI Trace or
Profile Normalization (Click)
20mSourceOffset.mat Matlab file (91x21) 91 frequencies, 21
stations hardwired input
SASW is Spectral Analysis of Surface Waves. Following description of data is from Dr. Brady Cox <brcox@utexas.edu>. Data were acquired in a benchmark project. Investigator analysis papers published by ASCE ISBN: 9780784413296 (GeoCongress 2014). Sample data from Christchurch NZ.
Acquisition Parameters Minimum sampling rate of 25.6 samples per second with time windows continuously adjusted by the analyzers for each frequency increment. Data provided in frequency domain only (i.e., linear spectrum from 10 â 1 Hz for each receiver). See included file, "UTexas1VibroseisData.txt", for additional details on data.
From within an octave session, type PseudoTime. This program, PseudoTime.m, takes data recorded in the frequency domain and creates pseudo-time domain traces through an inverse FFT. The negative frequency spectrum is a mirrored version of the positive frequency spectrum with opposite phase but same magnitude. Then inverse fft is called.
The differences between SASW.m and PseudoTime.m are in the source and type of data. The data sample for the SASW.m code are time domain signals while the data for PseudoTime.m are frequency domain converted to the time domain. The sample data sets are not from the same location, so there is no comparison to be made there. Even though the data set appears to be UTexas, that refers to those who collected the data, not the location, which in the case of this sample are from New Zealand.
actua
Figure 1 Time
domain traces created from the spectral recordings. One may
choose either
trace or profile scaling.
File: "data.txt" which contains the signals.
20mSourceOffset.mat data file in Matlab format.
OCTAVE: saswv.m(7) SASW.m(7) DispCurve.m(7)
No known bugs.
Copyright © 2017 by Paul Michaels
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
P. Michaels, PE. <pm@cgiss.boisestate.edu>