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In QRA64 decoder, downsample by 1/2 rather than 1/3. Fix some things in sync64 and spec64.

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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7316 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Joe Taylor 2016-11-14 19:56:13 +00:00
parent b04f70c5e7
commit 4334bf2fc3
4 changed files with 46 additions and 48 deletions

2
lib/jt65_decode.f90
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@ -99,7 +99,7 @@ contains
if(nsubmode.ge.100) then
! This is QRA64 mode
mode64=2**(nsubmode-100)
call qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mode64,mycall,hiscall, &
call qra64a(dd,npts,nutc,nf1,nf2,nfqso,ntol,mode64,mycall,hiscall, &
hisgrid,sync,nsnr,dtx,nfreq,decoded,nft)
if (associated(this%callback)) then
ndrift=0

38
lib/qra64a.f90
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@ -1,15 +1,15 @@
subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mode64,mycall_12,hiscall_12, &
subroutine qra64a(dd,npts,nutc,nf1,nf2,nfqso,ntol,mode64,mycall_12,hiscall_12, &
hisgrid_6,sync,nsnr,dtx,nfreq,decoded,nft)
use packjt
parameter (NFFT=2*6912,NZ=5760,NMAX=60*12000,LN=1152*63)
parameter (NMAX=60*12000,LN=1152*63)
character decoded*22
character*12 mycall_12,hiscall_12
character*6 mycall,hiscall,hisgrid_6
character*4 hisgrid
logical ltext
complex c00(0:360000) !Complex spectrum of dd()
complex c0(0:360000) !Complex spectrum of dd()
complex c00(0:720000) !Complex spectrum of dd()
complex c0(0:720000) !Complex data for dd()
! integer*8 count0,count1,clkfreq
real a(3)
real dd(NMAX) !Raw data sampled at 12000 Hz
@ -46,10 +46,14 @@ subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mode64,mycall_12,hiscall_12, &
ng2z=ng2
endif
maxf1=5
call sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snr1,c00)
npts2=216000
maxf1=0
call sync64(dd,npts,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snr1,c00)
npts2=npts/2
itz=10
if(mode64.eq.4) itz=9
if(mode64.eq.2) itz=7
if(mode64.eq.1) itz=5
naptype=4
LL=64*(mode64+2)
NN=63
@ -65,20 +69,19 @@ subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mode64,mycall_12,hiscall_12, &
idf1=itry1/2
if(mod(itry1,2).eq.0) idf1=-idf1
a(2)=-0.67*(idf1 + 0.67*kpk)
call twkfreq(c00,c0,npts2,4000.0,a)
call twkfreq(c00,c0,npts2,6000.0,a)
call spec64(c0,npts2,mode64,jpk,s3a,LL,NN)
ircmin=99
do iter=0,10
do iter=itz,0,-1
b90=1.728**iter
s3(1:LL*NN)=s3a(1:LL*NN)
call qra64_dec(s3,nc1,nc2,ng2,naptype,0,nSubmode,b90, &
nFadingModel,dat4,snr2,irc)
! if(irc.ge.0) write(*,3333) iter,idf0,-a(1),b90,irc
!3333 format(i2,i3,2f8.1,i3)
if(abs(snr2).gt.30.) snr2=-30.0
if(irc.eq.0) go to 10
! write(*,3001) iter,b90,snr2,irc
! write(72,3001) iter,b90,snr2,irc
!3001 format(i2,2f7.1,i4)
if(irc.ge.0 .and. irc.le.ircmin) then
if(irc.gt.0 .and. irc.le.ircmin) then
dat4x=dat4
b90x=b90
snr2x=snr2
@ -101,12 +104,7 @@ subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mode64,mycall_12,hiscall_12, &
else
snr2=0.
endif
! write(78,3900) nutc,snr1,snr2,dtx,nfreq,kpk,idf0,idf1,irc,decoded
!3900 format(i4.4,2f6.1,f6.2,i5,4i3,1x,a22)
! flush(78)
! write(*,3006) idf0,idf1,nfreq,jpk,kpk,irc,decoded
!3006 format(2i4,i6,i7,2i4,2x,a22)
if(irc.ge.0) go to 900
! if(irc.ge.0) go to 900
enddo
enddo
900 continue

17
lib/spec64.f90
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@ -1,31 +1,30 @@
subroutine spec64(c0,npts2,mode64,jpk,s3,LL,NN)
parameter (NSPS=2304) !Samples per symbol at 4000 Hz
parameter (NSPS=3456) !Samples per symbol at 6000 Hz
complex c0(0:360000) !Complex spectrum of dd()
complex cs(0:NSPS-1) !Complex symbol spectrum
real s3(LL,NN) !Synchronized symbol spectra
nfft6=nsps
fac=1.0/nfft6
do j=1,63
jj=j+7 !Skip first Costas array
if(j.ge.32) jj=j+14 !Skip middle Costas array
ja=jpk + (jj-1)*nfft6
jb=ja+nfft6-1
cs(0:nfft6-1)=c0(ja:jb)
cs(0:nfft6-1)=fac*c0(ja:jb)
call four2a(cs,nfft6,1,-1,1)
smax=0.
do ii=1,LL
i=ii-65
if(i.lt.0) i=i+nfft6
s3(ii,j)=real(cs(i))**2 + aimag(cs(i))**2
if(s3(ii,j).gt.smax) then
smax=s3(ii,j)
ipk=ii-65
endif
enddo
enddo
! df=4000.0/nfft6
! do i=1,LL
! freq=(i-65)*df
! write(73,3002) i-65,freq,(1.e-6*s3(i,j),j=1,5)
!3002 format(i5,6f10.3)
! enddo
return
end subroutine spec64

37
lib/sync64.f90
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@ -1,7 +1,8 @@
subroutine sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snrdb,c0)
subroutine sync64(dd,npts,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk, &
snrdb,c0)
parameter (NMAX=60*12000) !Max size of raw data at 12000 Hz
parameter (NSPS=2304) !Samples per symbol at 4000 Hz
parameter (NSPS=3456) !Samples per symbol at 6000 Hz
parameter (NSPC=7*NSPS) !Samples per Costas array
real dd(NMAX) !Raw data
real s1(0:NSPC-1) !Power spectrum of Costas 1
@ -14,7 +15,7 @@ subroutine sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snrdb,c0)
integer icos7(0:6) !Costas 7x7 tones
integer ipk0(1)
complex cc(0:NSPC-1) !Costas waveform
complex c0(0:360000) !Complex spectrum of dd()
complex c0(0:720000) !Complex spectrum of dd()
complex c1(0:NSPC-1) !Complex spectrum of Costas 1
complex c2(0:NSPC-1) !Complex spectrum of Costas 2
complex c3(0:NSPC-1) !Complex spectrum of Costas 3
@ -31,8 +32,8 @@ subroutine sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snrdb,c0)
k=-1
phi=0.
do j=0,6 !Compute complex Costas waveform
dphi=twopi*nsync*icos7(j)*dfgen/4000.0
do i=1,2304
dphi=twopi*nsync*icos7(j)*dfgen/6000.0
do i=1,NSPS
phi=phi + dphi
if(phi.gt.twopi) phi=phi-twopi
k=k+1
@ -42,20 +43,20 @@ subroutine sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snrdb,c0)
mode64z=mode64
endif
npts0=54*12000
nfft1=672000
nfft2=nfft1/3
nfft2=nfft1/2
df1=12000.0/nfft1
fac=2.0/nfft1
do i=0,nfft1/2 !Load real data into c0
c0(i)=fac*cmplx(dd(1+2*i),dd(2+2*i))
enddo
call four2a(c0,nfft1,1,-1,0) !Forward r2c FFT
c0(0:npts-1)=fac*dd(1:npts)
c0(npts:nfft1)=0.
call four2a(c0,nfft1,1,-1,1) !Forward c2c FFT
c0(nfft2/2+1:nfft2)=0.
c0(0)=0.5*c0(0)
call four2a(c0,nfft2,1,1,1) !Inverse c2c FFT; c0 is analytic sig
npts2=npts0/3 !Downsampled complex data length
npts2=npts/2 !Downsampled complex data length
nfft3=NSPC
nh3=nfft3/2
df3=4000.0/nfft3
df3=6000.0/nfft3
fa=max(nf1,nfqso-ntol)
fb=min(nf2,nfqso+ntol)
ia=max(maxf1,nint(fa/df3))
@ -64,7 +65,7 @@ subroutine sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snrdb,c0)
snr=0.
jpk=0
ja=0
jb=6*4000
jb=6*6000
jstep=200
ka=-maxf1
kb=maxf1
@ -72,8 +73,8 @@ subroutine sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snrdb,c0)
kpk=0
do iter=1,2
do j1=ja,jb,jstep
j2=j1 + 39*2304
j3=j1 + 77*2304
j2=j1 + 39*NSPS
j3=j1 + 77*NSPS
c1=1.e-4*c0(j1:j1+NSPC-1) * conjg(cc)
call four2a(c1,nfft3,1,-1,1)
c2=1.e-4*c0(j2:j2+NSPC-1) * conjg(cc)
@ -95,7 +96,7 @@ subroutine sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snrdb,c0)
s0b(:ia-1)=0.
s0b(ib+1:)=0.
nadd=(7*mode64)/2
if(mod(nadd,2).eq.1) nadd=nadd+1 !Make nadd odd
if(mod(nadd,2).eq.0) nadd=nadd+1 !Make nadd odd
if(nadd.ge.3) call smo(s0b(ia:ib),iz,s0(ia:ib),nadd)
call smo121(s0(ia:ib),iz)
nskip=max(14,2*mode64)
@ -105,7 +106,7 @@ subroutine sync64(dd,nf1,nf2,nfqso,ntol,mode64,maxf1,dtx,f0,jpk,kpk,snrdb,c0)
jpk=j1
s0a=s0/rms
snr=s
dtx=jpk/4000.0 - 1.0
dtx=jpk/6000.0 - 1.0
ipk0=maxloc(s0(ia:ib))
ipk=ipk0(1)
f0=(ipk+ia-1)*df3