sage.dsp.filters

Filename : filters.py Description : Short description of the file

Created on 2025-12-12 15:44:50

__author__ = Narenraju Nagarajan __copyright__ = Copyright 2025, ProjectName __license__ = MIT Licence __version__ = 0.0.1 __maintainer__ = Narenraju Nagarajan __affiliation__ = N/A __email__ = N/A __status__ = [‘inProgress’, ‘Archived’, ‘inUsage’, ‘Debugging’]

GitHub Repository: NULL

Documentation: NULL

Attributes

logger

Functions

pycbc_downsample(strain, old_sample_rate[, ...])

Resample and high-pass filter a strain time series via PyCBC.

highpass(x, fs[, cutoff, order, padlen_seconds, ...])

Robust zero-phase highpass using Butterworth SOS + filtfilt-like forward-backward.

Module Contents

logger[source]
pycbc_downsample(strain, old_sample_rate, new_sample_rate=2048.0, trim=0.2, noise_low_freq_cutoff=15.0)[source]

Resample and high-pass filter a strain time series via PyCBC.

Downsamples strain from old_sample_rate to new_sample_rate using PyCBC’s polyphase resampler, applies a high-pass filter at noise_low_freq_cutoff, converts to float32, and trims edge corruption introduced by the resampler.

Parameters:

  • strain (array-like, shape (N,)) – Input time series at old_sample_rate.

  • old_sample_rate (float) – Original sample rate in Hz.

  • new_sample_rate (float) – Target sample rate in Hz (default 2048.0).

  • trim (float) – Edge corruption to remove from each side in seconds (default 0.2).

  • noise_low_freq_cutoff (float) – High-pass cutoff frequency in Hz (default 15.0).

Returns:

Resampled and filtered strain with edges trimmed.

Return type:

numpy.ndarray, dtype float32

highpass(x, fs, cutoff=15.0, order=4, padlen_seconds=2.0, pad_type='reflect', fallback_to_sos=False)[source]

Robust zero-phase highpass using Butterworth SOS + filtfilt-like forward-backward. NOTE: Padding reduces edge effects

Parameters:

  • x (array) – 1D time series (float).

  • fs (float) – sampling rate (Hz).

  • cutoff (float) – cutoff frequency (Hz).

  • order (int) – nominal Butterworth order (sos built from order).

  • padlen_seconds (float) – pad length in seconds (mirror padding)

  • pad_type – ‘reflect’ or ‘odd’ or ‘constant’ (prefer ‘reflect’).

  • fallback_to_sos – if True and sosfiltfilt fails, do sosfilt (causal).

Returns:

filtered 1D array same length as input.

Return type:

y (np.ndarray)