36 lines
1.6 KiB
C
36 lines
1.6 KiB
C
#include "../libfm/fm.h"
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typedef struct ftmf_meas {
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double frequency_low;
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double frequency_high;
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double amplitude_low;
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double amplitude_high;
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int count;
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} dtmf_meas_t;
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typedef struct dtmf_dec {
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void *priv;
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void (*recv_digit)(void *priv, char digit, dtmf_meas_t *meas);
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int samplerate; /* samplerate */
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double freq_margin; /* +- limit of frequency deviation (percent) valid tone*/
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double min_amplitude; /* minimum amplitude relative to 0 dBm */
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double max_amplitude; /* maximum amplitude relative to 0 dBm */
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double forward_twist; /* how much do higher frequencies are louder than lower frequencies */
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double reverse_twist; /* how much do lower frequencies are louder than higher frequencies */
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int time_detect;
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int time_meas;
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int time_pause;
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fm_demod_t demod_low; /* demodulator for low frequencies */
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fm_demod_t demod_high; /* demodulator for high frequencies */
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iir_filter_t freq_lp[2]; /* low pass to filter the frequency result */
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char detected; /* currently detected DTMF digit or 0 for no detection */
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int count; /* counter to count detection or loss (pause) of signal */
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dtmf_meas_t meas; /* measurements */
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} dtmf_dec_t;
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int dtmf_decode_init(dtmf_dec_t *dtmf, void *priv, void (*recv_digit)(void *priv, char digit, dtmf_meas_t *meas), int samplerate, double max_amplitude, double min_amplitude);
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void dtmf_decode_exit(dtmf_dec_t *dtmf);
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void dtmf_decode(dtmf_dec_t *dtmf, sample_t *samples, int length);
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void dtmf_decode_filter(dtmf_dec_t *dtmf, sample_t *samples, int length, sample_t *frequency_low, sample_t *frequency_high, sample_t *amplitude_low, sample_t *amplitude_high);
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