w4kek/WSJT-X
1
0
Fork 0
mirror of https://github.com/saitohirga/WSJT-X.git synced 2024-11-27 06:38:44 -05:00
Code Issues Packages Projects Releases Wiki Activity

Refinements to wsprd_exp signal subtraction function.

Browse Source 
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@5624 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke 2015-06-21 01:48:48 +00:00
parent 9719ea02b4
commit 8c706f7f29
1 changed files with 18 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
lib/wsprd/wsprd_exp.c
View File

@ -389,7 +389,7 @@ void subtract_signal2(double *id, double *qd, long np,
float f0, int shift0, float drift0, unsigned char* channel_symbols)
{
double dt=1.0/375.0, df=375.0/256.0;
int i, j, k, ii;
int i, j, k, ii, nfilt=256; //nfilt must be even number.
double pi=4.*atan(1.0),twopidt;
double refi[45000],refq[45000];
@ -429,31 +429,31 @@ void subtract_signal2(double *id, double *qd, long np,
// s(t) * conjugate(r(t))
// place signal 1 impulse response width in so that we don't have to deal
// with partial convolutions at the beginning.
// with partial convolutions at the beginning when applying LPF.
for (i=0; i<41472; i++) {
k=shift0+i;
if( (k>0) & (k<np) ) {
ci[i+500] = id[k]*refi[i] + qd[k]*refq[i];
cq[i+500] = qd[k]*refi[i] - id[k]*refq[i];
ci[i+nfilt] = id[k]*refi[i] + qd[k]*refq[i];
cq[i+nfilt] = qd[k]*refi[i] - id[k]*refq[i];
}
}
//quick and dirty filter - may want to do better
double w[500], norm=0;
for (i=0; i<500; i++) {
w[i]=sin(pi*i/499.0);
double w[nfilt], norm=0;
for (i=0; i<nfilt; i++) {
w[i]=sin(pi*(float)i/(float)(nfilt-1));
norm=norm+w[i];
}
for (i=0; i<500; i++) {
for (i=0; i<nfilt; i++) {
w[i]=w[i]/norm;
}
// LPF
for (i=500; i<45000-375; i++) {
for (i=nfilt/2; i<45000-nfilt/2; i++) {
cfi[i]=0.0; cfq[i]=0.0;
for (j=0; j<500; j++) {
cfi[i]=cfi[i]+w[j]*ci[i-250+j];
cfq[i]=cfq[i]+w[j]*cq[i-250+j];
for (j=0; j<nfilt; j++) {
cfi[i]=cfi[i]+w[j]*ci[i-nfilt/2+j];
cfq[i]=cfq[i]+w[j]*cq[i-nfilt/2+j];
}
}
@ -462,8 +462,8 @@ void subtract_signal2(double *id, double *qd, long np,
for (i=0; i<41472; i++) {
k=shift0+i;
if( (k>0) & (k<np) ) {
id[k]=id[k] - (cfi[i+500]*refi[i]-cfq[i+500]*refq[i]);
qd[k]=qd[k] - (cfi[i+500]*refq[i]+cfq[i+500]*refi[i]);
id[k]=id[k] - (cfi[i+nfilt]*refi[i]-cfq[i+nfilt]*refq[i]);
qd[k]=qd[k] - (cfi[i+nfilt]*refq[i]+cfq[i+nfilt]*refi[i]);
}
}
return;
@ -748,9 +748,10 @@ int main(int argc, char *argv[])
if( ipass == 1 && uniques == 0 ) break;
if( ipass == 1 ) { //otherwise we bog down on the second pass
minsync1=0.18;
minsync2=0.2;
maxcycles=5000;
// minsync1=0.18;
// minsync2=0.2;
// maxcycles=5000;
quickmode = 1;
printf("-------------- 2 ----------------\n");
}