Version: 0.82 (using KDE 2.2.2) Installed from: Debian Package 4:2.2.2-13.woody.6 (3.0) Compiler: gcc version 2.95.4 20011002 (Debian prerelease) OS: Linux (i686) release 2.4.19-lac3 It would be really nice if there was a way to suppress low frequency noise (or signal, if one is so lucky) from a data vector. This would be very helpful for visualizing small signals riding on large low frequency noise fluctuations. When viewing PSDs of real data, this option would obviate the frequent autoscaling problem, in which the interesting part of the spectrum is dwarfed by the noise at low frequencies. A command line option to implement the "Low Frequency Interference" subtraction would be very convenient. The argument of the option could be the highpass edge in, say, units of the resolution element, or in Hz (if the sample rate is supplied as well). For instance, the command line of this sort kst -lfi 2 -r 200 would specify the sample rate (200 Hz), and the highpass edge of the filter required to overcome the low frequency noise in the data (2 Hz). Thanks, Bill
On Thursday 05 August 2004 15:54, William Jones wrote: > Version: 0.82 (using KDE 2.2.2) Wow that's old. Time to upgrade your Kst. :) http://extragear.kde.org/apps/kst.php > It would be really nice if there was a way to suppress low frequency noise > (or signal, if one is so lucky) from a data vector. This would be very > helpful for visualizing small signals riding on large low frequency noise > fluctuations. When viewing PSDs of real data, this option would obviate the > frequent autoscaling problem, in which the interesting part of the spectrum > is dwarfed by the noise at low frequencies. > > A command line option to implement the "Low Frequency Interference" > subtraction would be very convenient. The argument of the option could be > the highpass edge in, say, units of the resolution element, or in Hz (if > the sample rate is supplied as well). For instance, the command line of > this sort > > kst -lfi 2 -r 200 > > would specify the sample rate (200 Hz), and the highpass edge of the filter > required to overcome the low frequency noise in the data (2 Hz). Could this be done with a plugin? Recent Kst releases support plugins written in C. You can't quite reference them from the commandline, but they should be able to provide this functionality I think.
You can do this (though not from the command line) by using one of the Butterworth filter plugins. They came in several variations (high, low, band, and notch).
Do we need a command line interface for filters?
The feature, as requested, will not be implemented, as it is too special case. But, a new bug allowing command line implementation of plugins could be opened if a good UI could be come up with.