file4-o.txt

Reference Implementation of G.711 standard and other voice codecs

#include <stdio.h>
#include <string.h>
#include <math.h>
#include "gpib-bib.h"		/* header file for the NI488 software */
#include "hp8903b.h"		/* header file for the HP8903B */

int             main()
{
  /* GPIB variables */
  int             bd;
  HP8903B_state   st;

  /* Assign unique identifier to board 0 and save in bd */
  fprintf(stderr, "Initializing controller");
  if ((bd = ibfind("GPIB0")) < 0)
    return (GPIB_error(NULL), 1);

  /* Send the Interface Clear (IFC). */
  if (ibsic(bd) & ERR)
    return (GPIB_error(NULL), 1);

  /* Turn on Remote Enable (REN) signal so instrument can be programmed. */
  if (ibsre(bd, 1) & ERR)
    return (GPIB_error(NULL), 1);

  /* Reset devices */
  if (HP8903B_reset(bd))
    return (GPIB_error(NULL), 1);

  /* Initialize data structure with desired settings for the HP8903B */
  strcpy(st.src.uf, "HZ");	/* Frequency unity: Hz */
  strcpy(st.src.uv, "VL");	/* Amplitude unity: V */
  st.src.f = 1020;		/* 1020 Hz */
  st.src.v = 1;			/* 1V */

  /* Initialize the HP8903B */
  if (HP8903B_set_source(bd, st))
    exit(1);
  else
    fprintf(stderr, "\nHP8903B Source initialized!\n");


  /* Read measurement from HP8903 until something else than ENTER is hit */
  do
  {
    printf("\n");
    fprintf(stderr, ">> Hit ENTER repeat measurement, %s",
	    "any other key quit\n");
    printf(" AClevel= %11.3lfV\n", HP8903B_measure(LevelAC, bd, 4l));
    printf(" DClevel= %11.3lfV\n", HP8903B_measure(LevelDC, bd, 4l));
    printf(" SNR=     %10.2lfdB\n", HP8903B_measure(SNR, bd, 4l));
    printf(" SINAD=   %10.2lfdB\n", HP8903B_measure(SINAD, bd, 4l));
    printf(" Dist=    %12.4lfV\n", HP8903B_measure(Distortion, bd, 4l));
    printf(" Dist=    %12.4lf%%\n",
	   HP8903B_measure(DistortionPercent, bd, 4l));
  } while (getch() == '\r');

  /* The program terminates with an interface clear */
  ibsic(bd);

  /* Return OK */
  return (0);
}