Wrong PSD behavior


We are trying to calculate PSD using obspy.signal.psd.PPSD for accelerometric channels.
Sensor response is loaded from dataless SEED, where original units is M/S**2.
In this case PPSD always assumes the data is in velocity and applying differentiation to the channel data.
So from PQLX we got different results.
From psd.py:

         # go to acceleration, do nothing for rotational data:
         if self.is_rotational_data:
             tr.data = np.gradient(tr.data, self.delta)

It is possible to switch off response correction and also differentiation using is_rotational_data parameter,
but we need to correct response and the data already in acceleration units.

Aleksey Emanov

Hi Aleksey,

it sounds like you know exactly what you need in the processing, do you
have a code patch that does the right processing for you (just modify
the psd.py in your ObsPy installation)?
If you send me a patch I can work it in and it might even make it in the
upcoming stable release..