obspy.signal.filter.lowpass_cheby_2¶

lowpass_cheby_2(data, freq, df, maxorder=12, ba=False, freq_passband=False)[source]¶

Cheby2-Lowpass Filter

Filter data by passing data only below a certain frequency. The main purpose of this cheby2 filter is downsampling. #318 shows some plots of this filter design itself.

This method will iteratively design a filter, whose pass band frequency is determined dynamically, such that the values above the stop band frequency are lower than -96dB.

Parameters:	data (numpy.ndarray) Data to filter. freq The frequency above which signals are attenuated with 95 dB df Sampling rate in Hz. maxorder Maximal order of the designed cheby2 filter ba If True return only the filter coefficients (b, a) instead of filtering freq_passband If True return additionally to the filtered data, the iteratively determined pass band frequency
Returns:	Filtered data.