mirror of
https://github.com/signalwire/freeswitch.git
synced 2025-02-24 18:41:57 +00:00
10c6a30a59
It provides better detection than mod_vmd but is a little more CPU intensive than mod_vmd. Perhaps someone would like to CUDAfy this code?
37 lines
818 B
C
37 lines
818 B
C
#ifndef __GOERTZEL_H__
|
|
#include <math.h>
|
|
#include "goertzel.h"
|
|
#include "buffer.h"
|
|
|
|
/*! \brief Identify frequency components of a signal
|
|
* @author Eric des Courtis
|
|
* @param b A circular buffer
|
|
* @param pos Position in the buffer
|
|
* @param f Frequency to look at
|
|
* @param num Number of samples to look at
|
|
* @return A power estimate for frequency f at position pos in the stream
|
|
*/
|
|
extern double goertzel(circ_buffer_t *b, size_t pos, double f, size_t num)
|
|
{
|
|
double s = 0.0;
|
|
double p = 0.0;
|
|
double p2 = 0.0;
|
|
double coeff;
|
|
size_t i;
|
|
|
|
coeff = 2.0 * cos(2.0 * M_PI * f);
|
|
|
|
for(i = 0; i < num; i++){
|
|
/* TODO: optimize to avoid GET_SAMPLE when possible */
|
|
s = GET_SAMPLE(b, i + pos) + (coeff * p) - p2;
|
|
p2 = p;
|
|
p = s;
|
|
}
|
|
|
|
return (p2 * p2) + (p * p) - (coeff * p2 * p);
|
|
}
|
|
|
|
|
|
#endif
|
|
|