www.pudn.com > generate_trellis_nsc.rar > generate_trellis_nsc.c

// ------------------------------------------------------------------------ 
//         File: generate_trellis_nsc.c 
//         Date: April 1, 2002 
//  Description: Generate trellis data of a rate-1/n convolutional encoder 
//               of memory m 
// ------------------------------------------------------------------------ 
// This program is complementary material for the book: 
// 
// R.H. Morelos-Zaragoza, The Art of Error Correcting Coding, Wiley, 2002. 
// 
// ISBN 0471 49581 6 
// 
// This and other programs are available at http://the-art-of-ecc.com 
// 
// You may use this program for academic and personal purposes only.  
// If this program is used to perform simulations whose results are  
// published in a journal or book, please refer to the book above. 
// 
// The use of this program in a commercial product requires explicit 
// written permission from the author. The author is not responsible or  
// liable for damage or loss that may be caused by the use of this program.  
// 
// Copyright (c) 2002. Robert H. Morelos-Zaragoza. All rights reserved. 
// ------------------------------------------------------------------------ 
  
#include  
#include  
int k2=1, n2, m2;       // Code parameters 
int memory2, state;   // memory contents before and after encoding 
int data2, output;    // data bit and corresponding output bits 
void encoder2(void);           // Encoder 
int g2[10][10]; 
int NUMSTATWO, OUT_SYM, NUM_TRANS; 
 
 
main(int argc, char *argv[]) 
{ 
register int i, j, k, signal; 
char name1[40], name2[40]; 
FILE *fp1, *fp2; 
 
 
  // Command line processing 
  if (argc != 3) 
    { 
      printf("Usage %s file_input_parameters file_output\n", argv[0]); 
      exit(0); 
    } 
 
  sscanf(argv[1],"%s", name1); 
  sscanf(argv[2],"%s", name2); 
 
  fp1 = fopen(name1,"r"); 
  fscanf(fp1,"%d %d", &n2, &m2); 
  for (j=0; j=0; i--) 
	    { 
	      if ( (output >> i) & 1 ) 
		signal = -1;  // if bit = 1 
	      else 
		signal = +1;  // if bit = 0 
	      fprintf(fp2," %2d", signal); 
	    } 
	  fprintf(fp2,"\n"); 
	} 
    }  
  fclose(fp2); 
} 
 
 
 
 
void encoder2() 
{ 
  /* Conventional convolutional encoder, rate 1/n */ 
  register int i, j, result, temp; 
   
  temp = memory2; 
  output = 0; 
  temp = (temp<<1) ^ ( data2 & 0x01 ); 
  for (i=0; i=0; j--) 
       result ^= ( ( temp & g2[i][0] ) >> j ) & 1; 
     output = ( output<<1 ) ^ result; 
   } 
  state = temp & (NUMSTATWO-1); 
}