OpenRTX/openrtx/include/dsp.h

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2.9 KiB
C++

/***************************************************************************
* Copyright (C) 2020 by Federico Amedeo Izzo IU2NUO, *
* Niccolò Izzo IU2KIN, *
* Silvano Seva IU2KWO, *
* Frederik Saraci IU2NRO *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 3 of the License, or *
* (at your option) any later version. *
* *
* 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 General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, see <http://www.gnu.org/licenses/> *
***************************************************************************/
#ifndef DSP_H
#define DSP_H
#include <inttypes.h>
#include <stdlib.h>
typedef int16_t audio_sample_t;
/*
* This header contains various DSP utilities which can be used to condition
* input or output signals when implementing digital modes on OpenRTX.
*/
#ifdef __cplusplus
#include <array>
extern "C" {
#endif
/*
* Compensate for the filtering applied by the PWM output over the modulated
* signal. The buffer will be processed in place to save memory.
*
* @param buffer: the buffer to be used as both source and destination.
* @param length: the length of the input buffer.
*/
void dsp_pwmCompensate(audio_sample_t *buffer, uint16_t length);
/*
* Remove any DC bias from the audio buffer passed as parameter.
* The buffer will be processed in place to save memory.
*
* @param buffer: the buffer to be used as both source and destination.
* @param length: the length of the input buffer.
*/
void dsp_dcRemoval(audio_sample_t *buffer, uint16_t length);
#ifdef __cplusplus
}
/*
* Applies a generic FIR filter on the audio buffer passed as parameter.
* The buffer will be processed in place to save memory.
*
* @param buffer: the buffer to be used as both source and destination.
* @param length: the length of the input buffer.
* @param taps: an array of coefficients which defines the transfer function.
*/
template<size_t order>
void dsp_applyFIR(audio_sample_t *buffer,
uint16_t length,
std::array<float, order> taps);
#endif // __cplusplus
#endif /* DSP_H */