µVision4 User's Guide

Noise Signal

The following signal function generates a noise signal pattern. The input signal is provided to the VTREG AIN3. The variables volts, frequency, offset, and duration are used to adjust the signal.

/*----------------------------------------------------------------------
  Generate Noise Signal on AD Channel 3
----------------------------------------------------------------------*/
SIGNAL void AIN3_Noise (void)  {
  float volts;        // peak-to-peak volatage
  float frequency;    // output frequency in Hz
  float offset;       // volatge offset
  float duration;     // duration in Seconds
  float val;
  long  i, limited;

  volts     = 1.4;
  offset    = 1.6;
  duration  = 0.1;

  printf ("Noise Signal on AD Channel 3.\n");

  limited = (duration * 100000);
  for (i = 0 ; i < limited; i++)  {
    val =  ((float) rand(0)) / 32767.0;
    AIN3 = (val * volts) + offset;
    swatch (0.00001);                // in 10 uSec steps
  }
}

DEFINE BUTTON "AIN3 Noise","AIN3_Noise()"

Start debugging in simulation mode and drag the port into the Logic Analyzer. Open the Toolbox and click the button AIN3 Noise to view the signal output: