From 89e3fe24668d528af093714919f14a9996076b93 Mon Sep 17 00:00:00 2001
From: Mark Borgerding <mark@borgerding.net>
Date: Wed, 11 May 2005 03:02:57 +0000
Subject: [PATCH] *** empty log message ***

---
 test/twotonetest.c | 186 ++++++++++++++++++++-------------------------
 1 file changed, 81 insertions(+), 105 deletions(-)

diff --git a/test/twotonetest.c b/test/twotonetest.c
index 62fd55d..44f5f76 100644
--- a/test/twotonetest.c
+++ b/test/twotonetest.c
@@ -1,105 +1,81 @@
-#include <complex.h>
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-#include "kiss_fft.h"
-#include "kiss_fftr.h"
-#include <limits.h>
-
-#define pcpx(c)\
-        fprintf(stderr,"%g + %gi\n",(double)((c)->r),(double)((c)->i) )
-
-void fe_fft_test( int N, int bin1,int bin2)
-{
-    // static kiss_fft_cfg cfg = NULL;
-    static kiss_fftr_cfg cfg	= NULL;
-    static int lastN			= 0;
-    // kiss_fft_cpx *kin = NULL;
-    static kiss_fft_cpx *kout	= NULL;
-    static kiss_fft_scalar *kin_r = NULL;
-    static int halfN = 0;
-    int flipN;
-
-    int i;
-    double f1 = (bin1*2.0/N)*M_PI;
-    double f2 = (bin2*2.0/N)*M_PI;
-    double sigpow=0;
-    double noisepow=0;
-
-    if (lastN != N) {
-        // Free previous structures, if allocated.
-        if (cfg)
-            free(cfg);
-        if (kin_r)
-            free(kin_r);
-        if (kout)
-            free(kout);
-
-        halfN = N / 2;
-
-        // Allocate the KISS FFT configuration structure.
-        // Although the memory for these structures will be freed 
-        //  when the DLL unloads, to be squeaky clean it should be
-        //  freed explicitly.
-        // cfg = kiss_fft_alloc( N , 0, NULL, NULL);
-        cfg = kiss_fftr_alloc(N , 0, NULL, NULL);
-
-        // kin		= malloc(N * sizeof(kiss_fft_cpx));
-        // kin_r		= malloc(N * sizeof(kiss_fft_cpx));
-        kin_r		= malloc(N * sizeof(kiss_fft_scalar));
-        kout	= malloc(N * sizeof(kiss_fft_cpx));
-
-
-        lastN = N;
-    }
-
-#if FIXED_POINT==32
-    long maxrange = LONG_MAX;
-#else    
-    long maxrange = SHRT_MAX;
-#endif
-    // Convert the floating point "in" array to fixed point.
-    for (i = 0; i < N; i++)
-    {
-        kin_r[i] =  (maxrange>>1)*cos(f1*i)
-                  + (maxrange>>1)*cos(f2*i);
-    }
-
-    // Make the kiss FFT call.
-    kiss_fftr(cfg, kin_r, kout);
-
-    sigpow = 0;
-    //printf("[");
-    for (i=0;i < (N/2+1);++i) {
-        double tmpr = (double)kout[i].r / (double)maxrange;
-        double tmpi = (double)kout[i].i / (double)maxrange;
-        double mag2 = tmpr*tmpr + tmpi*tmpi;
-        if (i!=0 && i!= N/2)
-            mag2 *= 2; // all bins except DC and Nyquist have symmetric counterparts implied
-        sigpow += mag2;
-
-        // subtract out the expected result, anything left is noise
-        if ( i!=bin1 && i != bin2 ) 
-            noisepow += mag2;
-        //printf("%d%+di,",(int)kout[i].r,(int)kout[i].i);
-    }
-    //printf("]\n");
-    printf("TEST %d,%d,%d noise @ %fdB\n",N,bin1,bin2,10*log10(noisepow/sigpow +1e-20) );
-
-    return(0);
-}
-
-
-int main(int argc,char ** argv)
-{
-    int nfft = 16;
-    int i,j;
-    for (i=0;i<nfft/2;++i) { 
-        for (j=i;j<nfft/2;++j) {
-            fe_fft_test(nfft,i,j);
-        }
-    }
-    printf("sizeof(kiss_fft_scalar) = %d\n",sizeof(kiss_fft_scalar) );
-
-    return 0;
-}
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "kiss_fft.h"
+#include "kiss_fftr.h"
+#include <limits.h>
+
+#define pcpx(c)\
+        fprintf(stderr,"%g + %gi\n",(double)((c)->r),(double)((c)->i) )
+
+static
+double two_tone_test( int nfft, int bin1,int bin2)
+{
+    kiss_fftr_cfg cfg	= NULL;
+    kiss_fft_cpx *kout	= NULL;
+    kiss_fft_scalar *tbuf = NULL;
+
+    int i;
+    double f1 = bin1*2*M_PI/nfft;
+    double f2 = bin2*2*M_PI/nfft;
+    double sigpow=0;
+    double noisepow=0;
+
+    cfg = kiss_fftr_alloc(nfft , 0, NULL, NULL);
+    tbuf		= malloc(nfft * sizeof(kiss_fft_scalar));
+    kout	= malloc(nfft * sizeof(kiss_fft_cpx));
+    //assert(bin1<=nfft/2);
+    //assert(bin2<=nfft/2);
+
+#if FIXED_POINT==32
+    long maxrange = LONG_MAX;
+#else
+    long maxrange = SHRT_MAX;// works fine for float too
+#endif
+    // generate a signal with two tones
+    for (i = 0; i < nfft; i++) {
+        tbuf[i] =  (maxrange>>1)*cos(f1*i)
+                 + (maxrange>>1)*cos(f2*i);
+    }
+
+    kiss_fftr(cfg, tbuf, kout);
+
+    for (i=0;i < (nfft/2+1);++i) {
+        double tmpr = (double)kout[i].r / (double)maxrange;
+        double tmpi = (double)kout[i].i / (double)maxrange;
+        double mag2 = tmpr*tmpr + tmpi*tmpi;
+        if (i!=0 && i!= nfft/2)
+            mag2 *= 2; // all bins except DC and Nyquist have symmetric counterparts implied
+
+        // if there is power in one of the expected bins, it is signal, otherwise noise
+        if ( i!=bin1 && i != bin2 ) 
+            noisepow += mag2;
+        else
+            sigpow += mag2;
+    }
+    //printf("TEST %d,%d,%d noise @ %fdB\n",nfft,bin1,bin2,10*log10(noisepow/sigpow +1e-30) );
+    return 10*log10(sigpow/(noisepow+1e-50) );
+}
+
+int main(int argc,char ** argv)
+{
+    int nfft = 4*2*2*3*5;
+    int i,j;
+    double minsnr = 500;
+    double maxsnr = -500;
+    double snr;
+    for (i=0;i<nfft/2;++i) {
+        for (j=i;j<nfft/2;j+=7) {
+            snr = two_tone_test(nfft,i,j);
+            if (snr<minsnr) minsnr=snr;
+            if (snr>maxsnr) maxsnr=snr;
+        }
+    }
+    snr = two_tone_test(nfft,nfft/2,nfft/2);
+    if (snr<minsnr) minsnr=snr;
+    if (snr>maxsnr) maxsnr=snr;
+
+    printf("TwoToneTest: snr ranges from %ddB to %ddB\n",(int)minsnr,(int)maxsnr);
+    printf("sizeof(kiss_fft_scalar) = %d\n",sizeof(kiss_fft_scalar) );
+    return 0;
+}