--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/tests/noise_tests.c	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,280 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * noise_tests.c
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2005 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: noise_tests.c,v 1.9 2006/11/19 14:07:27 steveu Exp $
+ */
+
+/*! \page noise_tests_page Noise generator tests
+\section noise_tests_page_sec_1 What does it do?
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#if defined(HAVE_TGMATH_H)
+#include <tgmath.h>
+#endif
+#if defined(HAVE_MATH_H)
+#include <math.h>
+#endif
+#include <audiofile.h>
+#include <tiffio.h>
+
+#include "spandsp.h"
+
+#if !defined(M_PI)
+# define M_PI           3.14159265358979323846  /* pi */
+#endif
+
+#define OUT_FILE_NAME   "noise.wav"
+
+/* Some simple sanity tests for the noise generation routines */
+
+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;
+}
+/*- End of function --------------------------------------------------------*/
+/*- End of file ------------------------------------------------------------*/