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synced 2024-11-04 23:49:42 +02:00
usrp: support DCT in addition to complex FFT
- usrp/evscan (usage, main): treat all arguments but the last as options and pass them to "fft" - usrp/fft.c (fft_complex, do_fft): moved actual FFT calculation to separate function - usrp/fft.c (fft_real, do_fft): added real-valued FFT (DCT) as alternative - usrp/fft.c (main): undocumented option -a to set the FFT algorithm
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11
usrp/evscan
11
usrp/evscan
@ -2,17 +2,22 @@
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usage()
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{
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echo "usage: $0 base-dir" 1>&2
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echo "usage: $0 [options] base-dir" 1>&2
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exit 1
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}
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[ "$1" ] || usage
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opts=
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while [ "$2" ]; do
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opts="$opts $1"
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shift
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done
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[ -d "$1" ] || usage
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[ "$2" ] && usage
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for f in "$1"/24*; do
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echo -n `basename "$f"` ''
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for n in "$f"/data*; do
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./fft -s 100 0 20 50 <"$n" || echo "fft failed for $n" 1>&1
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./fft $opts -s 100 0 20 50 <"$n" || echo "fft failed for $n" 1>&1
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done | ./range -v 2
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done
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89
usrp/fft.c
89
usrp/fft.c
@ -9,13 +9,61 @@
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#define DEFAULT_THRESHOLD 100
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static int alg = 0;
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static void fft_complex(int n, const float *re, const float *im, double *res)
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{
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fftw_complex *in, *out;
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fftw_plan plan;
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int i;
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double a;
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in = fftw_malloc(sizeof(fftw_complex)*n);
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out = fftw_malloc(sizeof(fftw_complex)*n);
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for (i = 0; i != n; i++) {
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in[i][0] = re[i];
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in[i][1] = im[i];
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}
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plan = fftw_plan_dft_1d(n, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
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fftw_execute(plan);
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for (i = 0; i != n; i++) {
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a = hypot(out[i][0], out[i][1])/n;
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a = a*a;
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res[i] = a;
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}
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}
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static void fft_real(int n, const float *re, const float *im, double *res)
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{
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double *in;
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fftw_plan plan;
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int i;
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double a ;
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in = fftw_malloc(sizeof(double)*n);
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(void) a;
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for (i = 0; i != n; i++)
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in[i] = hypot(re[i], im[i]);
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plan = fftw_plan_r2r_1d(n, in, res, FFTW_REDFT10, FFTW_ESTIMATE);
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fftw_execute(plan);
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for (i = 0; i != n; i++)
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res[i] /= n;
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}
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static void do_fft(int skip, int dump, int low, int high, double threshold)
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{
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float c[2];
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float *re = NULL, *im = NULL;
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fftw_complex *in, *out;
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fftw_plan plan;
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double *res;
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int e = 0, n = 0;
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int i;
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double a;
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@ -58,23 +106,26 @@ static void do_fft(int skip, int dump, int low, int high, double threshold)
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im += skip;
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n -= skip;
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in = fftw_malloc(sizeof(fftw_complex)*n);
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out = fftw_malloc(sizeof(fftw_complex)*n);
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for (i = 0; i != n; i++) {
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in[i][0] = re[i];
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in[i][1] = im[i];
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res = malloc(n*sizeof(double));
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if (!res) {
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perror("malloc");
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exit(1);
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}
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plan = fftw_plan_dft_1d(n, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
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fftw_execute(plan);
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switch (alg) {
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case 0:
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fft_complex(n, re, im, res);
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break;
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case 1:
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fft_real(n, re, im, res);
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break;
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default:
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abort();
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}
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if (dump) {
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for (i = 0; i < n; i += 1) {
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a = hypot(out[i][0], out[i][1])/n;
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// a = a*a;
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printf("%d %g\n", i, 10*log(a)/log(10));
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}
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for (i = 0; i < n; i += 1)
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printf("%d %g\n", i, 10*log(res[i])/log(10));
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} else {
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double s = 0;
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double db;
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@ -91,8 +142,7 @@ static void do_fft(int skip, int dump, int low, int high, double threshold)
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if (low == high)
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low--;
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for (i = low; i != high; i++) {
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a = hypot(out[i][0], out[i][1])/n;
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// a = a*a;
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a = res[i];
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db = 10*log(a)/log(10);
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if (db >= threshold)
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s += a;
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@ -124,8 +174,11 @@ int main(int argc, char **argv)
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double threshold = DEFAULT_THRESHOLD;
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int c;
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while ((c = getopt(argc, argv, "ds:")) != EOF)
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while ((c = getopt(argc, argv, "a:ds:")) != EOF)
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switch (c) {
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case 'a':
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alg = atoi(optarg);
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break;
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case 'd':
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dump = 1;
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break;
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