question on zero-phase low-paas FIR filter

Users Mailing List Archive
1

Hi Everyone,

Is there any Obspy implementation of SAC’s zero-phase low-pass FIR filter that is applied before decimation ? I can see there is a function that might be similar but it says “Experimental code, use with caution” http://docs.obspy.org/packages/autogen/obspy.signal.filter.lowpass_fir.html#obspy.signal.filter.lowpass_fir . Thanks for your help.

Thanks.

Regards,

Avinash

2

Hi Avinash,

no we don’t have an implementation of SAC’s zero-phase low-pass FIR filter but any filter is zero-phase if you apply it forwards and backwards.

I’ve written this before on this list but I personally like to do: