WSJT-X/getfile.cpp

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#include "getfile.h"
#include <QDir>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
extern qint16 id[4*60*96000];
void getfile(QString fname, bool xpol, int dbDgrd)
{
int npts=2*52*96000;
if(xpol) npts=2*npts;
// Degrade S/N by dbDgrd dB -- for tests only!!
float dgrd=0.0;
if(dbDgrd<0) dgrd = 23.0*sqrt(pow(10.0,-0.1*(double)dbDgrd) - 1.0);
float fac=23.0/sqrt(dgrd*dgrd + 23.0*23.0);
memset(id,0,2*npts);
char name[80];
strcpy(name,fname.toLatin1());
FILE* fp=fopen(name,"rb");
if(fp != NULL) {
fread(&datcom_.fcenter,sizeof(datcom_.fcenter),1,fp);
fread(id,2,npts,fp);
int j=0;
if(dbDgrd<0) {
for(int i=0; i<npts; i+=2) {
datcom_.d4[j++]=fac*((float)id[i] + dgrd*gran());
datcom_.d4[j++]=fac*((float)id[i+1] + dgrd*gran());
if(!xpol) j+=2; //Skip over d4(3,x) and d4(4,x)
}
} else {
for(int i=0; i<npts; i+=2) {
datcom_.d4[j++]=(float)id[i];
datcom_.d4[j++]=(float)id[i+1];
if(!xpol) j+=2; //Skip over d4(3,x) and d4(4,x)
}
}
fclose(fp);
datcom_.ndiskdat=1;
int nfreq=(int)datcom_.fcenter;
if(nfreq!=144 and nfreq != 432 and nfreq != 1296) datcom_.fcenter=144.125;
int i0=fname.indexOf(".tf2");
if(i0<0) i0=fname.indexOf(".iq");
datcom_.nutc=0;
if(i0>0) {
datcom_.nutc=100*fname.mid(i0-4,2).toInt() + fname.mid(i0-2,2).toInt();
}
}
}
void savetf2(QString fname, bool xpol)
{
int npts=2*52*96000;
if(xpol) npts=2*npts;
qint16* buf=(qint16*)malloc(2*npts);
char name[80];
strcpy(name,fname.toLatin1());
FILE* fp=fopen(name,"wb");
if(fp != NULL) {
fwrite(&datcom_.fcenter,sizeof(datcom_.fcenter),1,fp);
int j=0;
for(int i=0; i<npts; i+=2) {
buf[i]=(qint16)datcom_.d4[j++];
buf[i+1]=(qint16)datcom_.d4[j++];
if(!xpol) j+=2; //Skip over d4(3,x) and d4(4,x)
}
fwrite(buf,2,npts,fp);
fclose(fp);
}
free(buf);
}
//#define MAX_RANDOM 0x7fffffff
/* Generate gaussian random float with mean=0 and std_dev=1 */
float gran()
{
float fac,rsq,v1,v2;
static float gset;
static int iset;
if(iset){
/* Already got one */
iset = 0;
return gset;
}
/* Generate two evenly distributed numbers between -1 and +1
* that are inside the unit circle
*/
do {
v1 = 2.0 * (float)rand() / RAND_MAX - 1;
v2 = 2.0 * (float)rand() / RAND_MAX - 1;
rsq = v1*v1 + v2*v2;
} while(rsq >= 1.0 || rsq == 0.0);
fac = sqrt(-2.0*log(rsq)/rsq);
gset = v1*fac;
iset++;
return v2*fac;
}