mirror of
git://projects.qi-hardware.com/ben-wpan.git
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e445fe1b01
- usrp/d.c: reduce the number of data points in a file produced by usrp2_rx_cfile.py and print them as text suitable for gnuplot - usrp/p.c: determine the peak amplitude in a series of transmissions, filtering noise and artefacts at the beginning of the data file - usrp/step: step through all channels and measure TX power (for antenna tuning) - usrp/Makefile: built "p" and "d"
67 lines
1006 B
C
67 lines
1006 B
C
#include <stdlib.h>
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#include <stdio.h>
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#include <math.h>
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#include <sys/types.h>
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#define PERC 0.9
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#define SKIP 1000000
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static int comp(const void *_a, const void *_b)
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{
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float a = *(const float *) _a;
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float b = *(const float *) _b;
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return a < b ? -1 : a > b;
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}
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int main(int argc, char **argv)
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{
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float max = 0;
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float c[2], a;
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float *rec = NULL;
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int e = 0, n = 0, skip = SKIP;
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while (1) {
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size_t s;
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s = fread(c, sizeof(c), 1, stdin);
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if (!s) {
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if (!ferror(stdin))
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break;
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if (s < 0) {
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perror("read");
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return 1;
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}
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}
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if (skip) {
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skip--;
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continue;
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}
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a = hypotf(c[0], c[1]);
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if (a > max)
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max = a;
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if (e <= n) {
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e = e ? e*2 : 10000;
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rec = realloc(rec, e*sizeof(float));
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if (!rec) {
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perror("realloc");
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exit(1);
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}
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}
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rec[n] = a;
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n++;
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}
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qsort(rec, n, sizeof(float), comp);
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printf("%f %f\n", max, rec[(int) (PERC*n)]);
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#if 0
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int i;
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for (i = 0; i < n; i += 1000)
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printf("%f %f\n", (double) i/n, rec[i]);
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#endif
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return 0;
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}
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