In file ../include/sigpr/EST_filter.h:

void FIRlowpass_double_filter

(const EST_Wave &in_sig,   EST_Wave &out_sig, int freq,   int order=DEFAULT_FILTER_ORDER)

Quick function for one-off zero phase high pass filtering.

Documentation

Quick function for one-off zero phase high pass filtering.

Normal high pass filtering (FIRhighpass_filter) introduces a time delay. This function filters the signal twice, first forward and then backwards, which ensures a zero phase lag. Hence the order parameter need only be half what it is for (FIRhighpass_filter to achieve the same effect.

Parameters:

in_sig - input waveform
out_sig - output waveform
- freq cutoff frequency in Hertz
order - number of filter coefficients, eg. 99

See Also:

FIRlowpass_filter

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This page is part of the Edinburgh Speech Tools Library documentation
Copyright University of Edinburgh 1997
Contact: speech_tools@cstr.ed.ac.uk