www.pudn.com > fast.zip > coder.h

/* segments of training sequence */ 
#define SEG_1	    0			/* ABAB...	 */ 
#define SEG_2	    (SEG_1 + 256)	/* CDCD...	 */ 
#define SEG_3	    (SEG_2 + 16)	/* TRN (A/C)	 */ 
#define SEG_4	    (SEG_3 + 256)	/* TRN (A/B/C/D) */ 
 
struct traininggen 
  { traininggen(scrambler *s) { scr = s; } 
    complex get(int); 
 
private: 
    scrambler *scr; 
  }; 
 
struct encoder 
  { encoder()	 { reset();		    } 
    void reset() { setrate(rb_4800); q = 0; } 
    void setrate(ushort); 
    complex encode(int); 
    ushort rate; 
 
private: 
    int q, t; 
  }; 
 
#define TLEN	20		/* num. of columns in trellis, = 5 * constraint length */ 
#define NSTATES 8		/* num. of states in convolutional encoder */ 
#define NINPUTS 4		/* num. inputs to convolutional encoder (1 << k) */ 
 
typedef unsigned long long u64bit; 
 
struct tnode 
  { tnode *fwd[NINPUTS];	/* paths leading forwards in trellis */ 
    float svlen;		/* path length (metric) for surviving path terminating here */ 
    u64bit path;		/* path code to this point */ 
  }; 
 
struct decoder 
  { decoder()	 { inittrellis(); reset();  } 
    void reset() { setrate(rb_4800); q = 0; }	/* no need to re-init trellis; we haven't used it yet */ 
    void printtrellis(char*); 
    void setrate(ushort); 
    int decode(complex); 
    complex getez(); 
    ushort rate; 
 
private: 
    void inittrellis(); 
    int viterbi(complex); 
    tnode trellis[TLEN][NSTATES]; 
    int tindex, q; 
    complex pz; /* for getez */ 
  }; 
 
extern c_complex ztab2[];