int main (int argc, char *argv[])
{
int i;
int j;
int level;
int clip_high;
int clip_low;
int total_samples;
int seed = 1234567;
int outframes;
int16_t value;
double total;
double x;
double p;
double o;
int bins[65536];
int16_t amp[1024];
noise_state_t noise_source;
AFfilehandle outhandle;
AFfilesetup filesetup;
if ((filesetup = afNewFileSetup()) == AF_NULL_FILESETUP)
{
fprintf(stderr, " Failed to create file setup\n");
exit(2);
}
afInitSampleFormat(filesetup, AF_DEFAULT_TRACK, AF_SAMPFMT_TWOSCOMP, 16);
afInitRate(filesetup, AF_DEFAULT_TRACK, (float) SAMPLE_RATE);
afInitFileFormat(filesetup, AF_FILE_WAVE);
afInitChannels(filesetup, AF_DEFAULT_TRACK, 1);
if ((outhandle = afOpenFile(OUT_FILE_NAME, "w", filesetup)) == AF_NULL_FILEHANDLE)
{
fprintf(stderr, " Cannot create wave file '%s'\n", OUT_FILE_NAME);
exit(2);
}
/* Generate AWGN at several RMS levels between -50dBOv and 0dBOv. Noise is
generated for a large number of samples (1,000,000), and the RMS value
of the noise is calculated along the way. If the resulting level is
close to the requested RMS level, at least the scaling of the noise
should be Ok. At high levels some clipping may distort the result a
little. */
printf("Testing with quality 7 AWGN\n");
for (level = -50; level <= 0; level += 5)
{
clip_high = 0;
clip_low = 0;
total = 0.0;
noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, 7);
total_samples = 1000000;
for (i = 0; i < total_samples; i++)
{
value = noise(&noise_source);
if (value == 32767)
clip_high++;
else if (value == -32768)
clip_low++;
total += ((double) value)*((double) value);
}
printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
log10(sqrt(total/total_samples)/32768.0)*20.0,
level,
100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
clip_low,
clip_high);
if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
{
printf("Test failed\n");
exit(2);
}
}
printf("Testing with quality 20 AWGN\n");
for (level = -50; level <= 0; level += 5)
{
clip_high = 0;
clip_low = 0;
total = 0.0;
noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, 20);
total_samples = 1000000;
for (i = 0; i < total_samples; i++)
{
value = noise(&noise_source);
if (value == 32767)
clip_high++;
else if (value == -32768)
clip_low++;
total += ((double) value)*((double) value);
}
printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
log10(sqrt(total/total_samples)/32768.0)*20.0,
level,
100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
clip_low,
clip_high);
if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
{
printf("Test failed\n");
exit(2);
}
}
/* Now look at the statistical spread of the results, by collecting data in
bins from a large number of samples. Use a fairly high noise level, but
low enough to avoid significant clipping. Use the Gaussian model to
predict the real probability, and present the results for graphing. */
memset(bins, 0, sizeof(bins));
clip_high = 0;
clip_low = 0;
level = -15;
noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, 7);
total_samples = 10000000;
for (i = 0; i < total_samples; i++)
{
value = noise(&noise_source);
if (value == 32767)
clip_high++;
else if (value == -32768)
clip_low++;
bins[value + 32768]++;
}
/* Find the RMS power level to expect */
o = pow(10.0, level/20.0)*(32768.0*0.70711);
for (i = 0; i < 65536 - 10; i++)
{
x = i - 32768;
/* Find the real probability for this bin */
p = (1.0/(o*sqrt(2.0*M_PI)))*exp(-(x*x)/(2.0*o*o));
/* Now do a little smoothing on the real data to get a reasonably
steady answer */
x = 0;
for (j = 0; j < 10; j++)
x += bins[i + j];
x /= 10.0;
x /= total_samples;
/* Now send it out for graphing. */
if (p > 0.0000001)
printf("%6d %.7f %.7f\n", i - 32768, x, p);
}
printf("Generating AWGN at -15dBOv to file\n");
for (j = 0; j < 50; j++)
{
for (i = 0; i < 1024; i++)
amp[i] = noise(&noise_source);
outframes = afWriteFrames(outhandle,
AF_DEFAULT_TRACK,
amp,
1024);
if (outframes != 1024)
{
fprintf(stderr, " Error writing wave file\n");
exit(2);
}
}
/* Generate AWGN at several RMS levels between -50dBm and 0dBm. Noise is
generated for a large number of samples (1,000,000), and the RMS value
of the noise is calculated along the way. If the resulting level is
close to the requested RMS level, at least the scaling of the noise
should be Ok. At high levels some clipping may distort the result a
little. */
printf("Testing with quality 7 Hoth noise.\n");
for (level = -50; level <= 0; level += 5)
{
clip_high = 0;
clip_low = 0;
total = 0.0;
noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_HOTH, 7);
total_samples = 1000000;
for (i = 0; i < total_samples; i++)
{
value = noise(&noise_source);
if (value == 32767)
clip_high++;
else if (value == -32768)
clip_low++;
total += ((double) value)*((double) value);
}
printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
log10(sqrt(total/total_samples)/32768.0)*20.0,
level,
100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
clip_low,
clip_high);
if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
{
printf("Test failed\n");
exit(2);
}
}
printf("Generating Hoth noise at -15dBOv to file\n");
level = -15;
noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_HOTH, 7);
for (j = 0; j < 50; j++)
{
for (i = 0; i < 1024; i++)
amp[i] = noise(&noise_source);
outframes = afWriteFrames(outhandle,
AF_DEFAULT_TRACK,
amp,
1024);
if (outframes != 1024)
{
fprintf(stderr, " Error writing wave file\n");
exit(2);
}
}
if (afCloseFile(outhandle))
{
fprintf(stderr, " Cannot close wave file '%s'\n", OUT_FILE_NAME);
exit(2);
}
afFreeFileSetup(filesetup);
printf("Tests passed.\n");
return 0;
}
int main (int argc, char *argv[])
{
int i;
int j;
int level;
int clip_high;
int clip_low;
int quality;
int total_samples;
int seed = 1234567;
int outframes;
int16_t value;
double total;
double x;
double p;
double o;
int bins[65536];
int16_t amp[1024];
noise_state_t noise_source;
SNDFILE *outhandle;
if ((outhandle = sf_open_telephony_write(OUT_FILE_NAME, 1)) == NULL)
{
fprintf(stderr, " Cannot create audio file '%s'\n", OUT_FILE_NAME);
exit(2);
}
for (quality = 7; quality <= 20; quality += (20 - 7))
{
/* Generate AWGN at several RMS levels between -50dBOv and 0dBOv. Noise is
generated for a large number of samples (1,000,000), and the RMS value
of the noise is calculated along the way. If the resulting level is
close to the requested RMS level, at least the scaling of the noise
should be Ok. At high levels some clipping may distort the result a
little. */
printf("Testing AWGN power, with quality %d\n", quality);
for (level = -50; level <= 0; level += 5)
{
clip_high = 0;
clip_low = 0;
total = 0.0;
noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, quality);
total_samples = 1000000;
for (i = 0; i < total_samples; i++)
{
value = noise(&noise_source);
if (value == 32767)
clip_high++;
else if (value == -32768)
clip_low++;
total += ((double) value)*((double) value);
}
printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
log10(sqrt(total/total_samples)/32768.0)*20.0,
level,
100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
clip_low,
clip_high);
if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
{
printf("Test failed\n");
exit(2);
}
}
}
/* Now look at the statistical spread of the results, by collecting data in
bins from a large number of samples. Use a fairly high noise level, but
low enough to avoid significant clipping. Use the Gaussian model to
predict the real probability, and present the results for graphing. */
quality = 7;
printf("Testing the statistical spread of AWGN, with quality %d\n", quality);
memset(bins, 0, sizeof(bins));
clip_high = 0;
clip_low = 0;
level = -15;
noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, quality);
total_samples = 10000000;
for (i = 0; i < total_samples; i++)
{
value = noise(&noise_source);
if (value == 32767)
clip_high++;
else if (value == -32768)
clip_low++;
bins[value + 32768]++;
}
/* Find the RMS power level to expect */
o = pow(10.0, level/20.0)*(32768.0*0.70711);
for (i = 0; i < 65536 - 10; i++)
{
x = i - 32768;
/* Find the real probability for this bin */
p = (1.0/(o*sqrt(2.0*M_PI)))*exp(-(x*x)/(2.0*o*o));
/* Now do a little smoothing on the real data to get a reasonably
steady answer */
x = 0;
for (j = 0; j < 10; j++)
x += bins[i + j];
x /= 10.0;
x /= total_samples;
/* Now send it out for graphing. */
if (p > 0.0000001)
printf("%6d %.7f %.7f\n", i - 32768, x, p);
}
printf("Generating AWGN at -15dBOv to file\n");
for (j = 0; j < 50; j++)
{
for (i = 0; i < 1024; i++)
amp[i] = noise(&noise_source);
outframes = sf_writef_short(outhandle, amp, 1024);
if (outframes != 1024)
{
fprintf(stderr, " Error writing audio file\n");
exit(2);
}
}
/* Generate Hoth noise at several RMS levels between -50dBm and 0dBm. Noise
is generated for a large number of samples (1,000,000), and the RMS value
of the noise is calculated along the way. If the resulting level is
close to the requested RMS level, at least the scaling of the noise
should be Ok. At high levels some clipping may distort the result a
little. */
quality = 7;
printf("Testing Hoth noise power, with quality %d\n", quality);
for (level = -50; level <= 0; level += 5)
{
clip_high = 0;
clip_low = 0;
total = 0.0;
noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_HOTH, quality);
total_samples = 1000000;
for (i = 0; i < total_samples; i++)
{
value = noise(&noise_source);
if (value == 32767)
clip_high++;
else if (value == -32768)
clip_low++;
total += ((double) value)*((double) value);
}
printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
log10(sqrt(total/total_samples)/32768.0)*20.0,
level,
100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
clip_low,
clip_high);
if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
{
printf("Test failed\n");
exit(2);
}
}
quality = 7;
printf("Generating Hoth noise at -15dBOv to file\n");
level = -15;
noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_HOTH, quality);
for (j = 0; j < 50; j++)
{
for (i = 0; i < 1024; i++)
amp[i] = noise(&noise_source);
outframes = sf_writef_short(outhandle, amp, 1024);
if (outframes != 1024)
{
fprintf(stderr, " Error writing audio file\n");
exit(2);
}
}
if (sf_close(outhandle))
{
fprintf(stderr, " Cannot close audio file '%s'\n", OUT_FILE_NAME);
exit(2);
}
printf("Tests passed.\n");
return 0;
}
