Power spectral density PDFs

Users Mailing List Archive
1

I’d like to calculate PSD PDFs using PPSD in ObsPy.

I have already done some processing of the data and the instrument response is removed.

Is it possible for PPSD to ‘know’ that an instrument response is already removed and the trace units are in velocity (as opposed to counts) to ensure that instrument response is not removed twice?

Or do I somehow have to somehow restore the instrument response before using PPSD?

Thanks,
Steve

2

Short answer: You should use the raw data and station metadata whenever
possible.

Long answer:
In principle you might be able to misuse the PPSD(...,
special_handling='ringlaser') setting and using a dictionary with
'sensitivity': 1 as `metadata`. But you're on your own with this special
tinkering. I'd really recommend you use raw data and station metadata.

cheers,
T

P.S.: How do you expect PPSD to know what units the data is you feed it?
There is no way for PPSD to know this, in general it is assumed that all
data that enter it are raw digitized data (i.e. the data described by
station metadata in SEED or StationXML)

3

You can supply a dummy paz with sensitivity 1 to already corrected data.

paz = {‘gain’: 1.,
‘poles’: [],
‘zeros’: [],
‘sensitivity’: 1.}

Cheers
Christian

4

You can supply a dummy paz with sensitivity 1 to already corrected data.

paz = {‘gain’: 1.,
‘poles’: [],
‘zeros’: [],
‘sensitivity’: 1.}

Cheers
Christian