freeswitch/libs/spandsp/src/filter_tools.h

58 lines
1.8 KiB
C

/*
* SpanDSP - a series of DSP components for telephony
*
* filter_tools.h - A collection of routines used for filter design.
*
* Written by Steve Underwood <steveu@coppice.org>
*
* Copyright (C) 2008 Steve Underwood
*
* Based on:
* mkshape -- design raised cosine FIR filter
* A.J. Fisher, University of York <fisher@minster.york.ac.uk>, November 1996
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#if !defined(_FILTER_TOOLS_H_)
#define _FILTER_TOOLS_H_
#if defined(__cplusplus)
extern "C"
{
#endif
void ifft(complex_t data[], int len);
void apply_hamming_window(double coeffs[], int len);
void truncate_coeffs(double coeffs[], int len, int bits, int hilbert);
void compute_raised_cosine_filter(double coeffs[],
int len,
int root,
int sinc_compensate,
double alpha,
double beta);
void compute_hilbert_transform(double coeffs[], int len);
#if defined(__cplusplus)
}
#endif
#endif
/*- End of file ------------------------------------------------------------*/