Q65: compute snr from esnodb, using actual symbol rate.

This commit is contained in:
Joe Taylor 2020-10-30 14:52:58 -04:00
parent 306c0c8633
commit b3f0aec407
2 changed files with 8 additions and 7 deletions

View File

@ -69,7 +69,7 @@ subroutine q65_loops(c00,npts2,nsps,mode,mode64,nsubmode,nFadingModel, &
ncall=ncall+1
call timer('qra64_de',0)
call q65_intrinsics_ff(s3,nsubmode,b90,nFadingModel,s3prob)
call q65_dec(s3,s3prob,APmask,APsymbols,snr2,dat4,irc)
call q65_dec(s3,s3prob,APmask,APsymbols,esnodb,dat4,irc)
! irc > 0 ==> number of iterations required to decode
! -1 = invalid params
! -2 = decode failed
@ -84,8 +84,7 @@ subroutine q65_loops(c00,npts2,nsps,mode,mode64,nsubmode,nFadingModel, &
a(1)=-f0
call twkfreq(c00,c0,npts2,6000.0,a)
jpk=3000 !### These definitions need work ###
! if(nsps.ge.3600) jpk=4080 !###
if(nsps.ge.3600) jpk=6000 !###
if(nsps.ge.3600) jpk=6000 !### TR >= 60 s
call spec64(c0,nsps,mode,mode64,jpk,s3,LL,NN)
call pctile(s3,LL*NN,40,base)
s3=s3/base
@ -100,6 +99,8 @@ subroutine q65_loops(c00,npts2,nsps,mode,mode64,nsubmode,nFadingModel, &
if(irc.ge.0) then
navg=nsave
baud=6000.0/nsps
snr2=esnodb - db(2500.0/baud)
if(iavg.eq.0) navg=0
!### For tests only:
open(53,file='fort.53',status='unknown',position='append')

View File

@ -77,14 +77,14 @@ void q65_intrinsics_ff_(float s3[], int* submode, float* B90,
}
void q65_dec_(float s3[], float s3prob[], int APmask[], int APsymbols[],
float* snr2500, int xdec[], int* rc0)
float* esnodb0, int xdec[], int* rc0)
{
/* Input: s3prob[LL,NN] Symbol-value intrinsic probabilities
* APmask[13] AP information to be used in decoding
* APsymbols[13] Available AP informtion
* Output:
* snr2500 SNR_2500 of decoded signal, or lower limit
* esnodb0 Estimated Es/No in dB
* xdec[13] Decoded 78-bit message as 13 six-bit integers
* rc0 Return code from q65_decode()
*/
@ -98,7 +98,7 @@ void q65_dec_(float s3[], float s3prob[], int APmask[], int APsymbols[],
// rc = -1: Invalid params
// rc = -2: Decode failed
// rc = -3: CRC mismatch
*snr2500 = -31.0;
*esnodb0 = 0.0; //Default Es/No for a failed decode
if(rc<0) return;
rc = q65_esnodb_fastfading(&codec,&esnodb,ydec,s3);
@ -106,5 +106,5 @@ void q65_dec_(float s3[], float s3prob[], int APmask[], int APsymbols[],
printf("error in q65_esnodb_fastfading()\n");
exit(0);
}
*snr2500 = esnodb - 31.0;
*esnodb0 = esnodb;
}