v22.h

Linmodem is soft modem source code for embedded system

enum ModulationType {
    V34_MOD_600,
    V22_MOD_600,
    V22_MOD_1200,
    V22_MOD_2400, 
};

/* 40 phases (sure too much, but we don't optimize right now) */
#define V22_TX_FILTER_SIZE (20 * 40)
#define V22_TX_BUF_SIZE    64

typedef struct {
    /* parameters */
    int calling;
    enum ModulationType mod_type;         
    void *opaque;
    get_bit_func get_bit;

    /* state */
    int baud_phase, baud_num, baud_denom;
    int carrier_phase, carrier_incr;
    int carrier2_phase, carrier2_incr;
    int tx_filter_wsize;
    s16 tx_buf[V22_TX_BUF_SIZE][2];  /* complex symbols to be sent */
    int tx_outbuf_ptr;               /* index of the next symbol in tx_buf */
    int Z;              /* last value transmitted */
} V22ModState;

typedef struct {
    /* parameters */
    int calling;
    enum ModulationType mod_type;
    void *opaque;
    put_bit_func put_bit;

    int baud_phase, baud_num, baud_denom;
    int carrier_phase, carrier_incr;
} V22DemodState;

extern s16 v22_tx_filter[V22_TX_FILTER_SIZE];

void V22_mod_init(V22ModState *s);
void V22_mod(V22ModState *s, s16 *samples, unsigned int nb);

void V22_test(void);