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#ifndef __DSSS_DEMOD_H__
#define __DSSS_DEMOD_H__
#define DSSS_GOLD_CODE_LENGTH ((1<<DSSS_GOLD_CODE_NBITS) - 1)
#define DSSS_GOLD_CODE_COUNT ((1<<DSSS_GOLD_CODE_NBITS) + 1)
#define DSSS_CORRELATION_LENGTH (DSSS_GOLD_CODE_LENGTH * DSSS_DECIMATION)
#define PAYLOAD_DATA_BYTE ((PAYLOAD_DATA_BIT+7)/8)
struct iir_biquad {
float a[2];
float b[3];
};
struct iir_biquad_state {
float reg[2];
};
struct cwt_iir_filter_state {
struct iir_biquad_state st[3];
};
struct {
int len; /* length of group in samples */
float max; /* signed value of largest peak in group on any channel */
uint64_t max_ts; /* absolute position of above peak */
int max_ch; /* channel (gold sequence index) of above peak */
} group;
struct decoder_state {
int last_phase;
int candidate_phase;
float last_score;
float candidate_score;
uint8_t data[PAYLOAD_DATA_BYTE];
int data_pos;
};
struct dsss_demod_state {
float signal[DSSS_CORRELATION_LENGTH];
size_t signal_wpos;
float correlation[DSSS_GOLD_CODE_COUNT][DSSS_WAVELET_LUT_SIZE];
size_t correlation_wpos;
struct cwt_iir_filter_state cwt_filter[DSSS_GOLD_CODE_COUNT];
struct group group;
struct group group_cache[DSSS_GROUP_CACHE_SIZE];
};
#ifdef SIMULATION
void dsss_demod_step(struct dsss_demod_state *st, float new_value, uint64_t ts, int record_channel);
#else /* SIMULATION */
void dsss_demod_step(struct dsss_demod_state *st, float new_value, uint64_t ts);
#endif /* SIMULATION */
#endif /* __DSSS_DEMOD_H__ */
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