Working on DSSS demodulator sim

1 files changed, 44 insertions, 0 deletions

diff --git a/controller/fw/src/dsss_demod.h b/controller/fw/src/dsss_demod.h
new file mode 100644
index 0000000..8ab5cac
--- /dev/null
+++ b/controller/fw/src/dsss_demod.h
@@ -0,0 +1,44 @@
+#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)
+
+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 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 {
+        int len; /* length of group in samples */
+        float max; /* signed value of largest peak in group on any channel */
+        int max_idx; /* position of above peak counted from start of group */
+        int max_ch; /* channel (gold sequence index) of above peak */
+    } group;
+};
+
+#ifdef SIMULATION
+void dsss_demod_step(struct dsss_demod_state *st, float new_value, size_t sim_pos);
+#else /* SIMULATION */
+void dsss_demod_step(struct dsss_demod_state *st, float new_value);
+#endif /* SIMULATION */
+
+#endif /* __DSSS_DEMOD_H__ */