Removing instrument response for accelerometers

So, I am trying to remove instrument response from some acceleration instruments and am encountering a strange behavior. The accelerometer instruments have no poles and so I am getting an error from the scipy.signal routines used to build frequency response or remove the instrument response. The error is included below for completeness. Has anybody seen this problem? Does anybody have suggestions on how to treat instrument response information with no poles.


Hi Austin,

This looks like an ObsPy bug to me. I therefore submitted a bug report with your message. I hope that's ok.

To resolve this it would be very helpful if you could send me one of your files together with the zeros-information.


I will send the files directly to you then.

I found a work around by adding an equal pole and zero at a frequency well
outside the range of concern I can eliminate this problem. That is
probably reasonable to do because no instrument has a flat response from
DC to infinity.

Hi Austin,

Great, that you got it working. I will fix the bug, anyway. You can send the file either to me or attach it to the bug report that I just submitted on the obspy webpage (ticket # 281).


Hi Yannik, hi Austin,

was curious what was going wrong and submitted a fix [2668], it should
work now. I am not working with accelerometer data, would be great if
you could check if it works as expected.


Yannik Behr wrote:

Hi Austin and Tobi,

Thanks for the fix, Tobi. It would be great if you could send me one of your data files, Austin, so I can build a test for this bug. If you don't feel like giving away any data you could rename your station etc. to something generic.