1 files changed, 40 insertions, 0 deletions
diff --git a/src/libfm/fm.h b/src/libfm/fm.h
new file mode 100644
index 0000000..b87a662
--- /dev/null
+++ b/src/libfm/fm.h
@@ -0,0 +1,40 @@
+#include "../libfilter/iir_filter.h"
+
+int fm_init(int fast_math);
+void fm_exit(void);
+
+enum fm_mod_state {
+	MOD_STATE_OFF,		/* transmitter off, no IQ vector */
+	MOD_STATE_ON,		/* transmitter on, FM modulated IQ vector */
+	MOD_STATE_RAMP_UP,	/* use half cos to ramp up IQ vector */
+	MOD_STATE_RAMP_DOWN,	/* use half cos to ramp down IQ vector */
+};
+
+typedef struct fm_mod {
+	double samplerate;	/* sample rate of in and out */
+	double offset;		/* offset to calculated center frequency */
+	double amplitude;	/* how much amplitude to add to the buff */
+	double phase;		/* current phase of FM (used to shift and modulate ) */
+	enum fm_mod_state state;/* state of transmit power */
+	double *ramp_tab;	/* half cosine ramp up */
+	int ramp;		/* current ramp position */
+	int ramp_length;	/* number of values in ramp */
+} fm_mod_t;
+
+int fm_mod_init(fm_mod_t *mod, double samplerate, double offset, double amplitude);
+void fm_mod_exit(fm_mod_t *mod);
+void fm_modulate_complex(fm_mod_t *mod, sample_t *frequency, uint8_t *power, int num, float *baseband);
+
+typedef struct fm_demod {
+	double samplerate;	/* sample rate of in and out */
+	double phase;		/* current rotation phase (used to shift) */
+	double rot;		/* rotation step per sample to shift rx frequency (used to shift) */
+	double last_phase;	/* last phase of FM (used to demodulate) */
+	iir_filter_t lp[2];	/* filters received IQ signal */
+} fm_demod_t;
+
+int fm_demod_init(fm_demod_t *demod, double samplerate, double offset, double bandwidth);
+void fm_demod_exit(fm_demod_t *demod);
+void fm_demodulate_complex(fm_demod_t *demod, sample_t *frequency, int length, float *baseband, sample_t *I, sample_t *Q);
+void fm_demodulate_real(fm_demod_t *demod, sample_t *frequency, int length, sample_t *baseband, sample_t *I, sample_t *Q);
+