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About 1 dB better for worst-case DT. Further improvement still to come!

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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6935 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Joe Taylor 2016-07-21 15:23:32 +00:00
parent c7361c66f6
commit 6d6fa2b4ae
1 changed files with 60 additions and 25 deletions
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85
lib/qra64a.f90
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@ -1,8 +1,8 @@
subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12,hisgrid_6, &
sync,nsnr,dtx,nfreq,decoded,nft)
subroutine qra64a(dd0,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12, &
hisgrid_6,sync,nsnr,dtx,nfreq,decoded,nft)
use packjt
parameter (NFFT=2*6912,NH=NFFT/2,NZ=5760)
parameter (NFFT=2*6912,NH=NFFT/2,NZ=5760,NMAX=60*12000)
character decoded*22
character*12 mycall_12,hiscall_12
character*6 mycall,hiscall,hisgrid_6
@ -11,13 +11,11 @@ subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12,hisgrid_6, &
integer*8 count0,count1,clkfreq
integer icos7(0:6)
integer dat4(12)
real dd(60*12000)
real dd0(NMAX),dd(NMAX)
real s(NZ)
real savg(NZ)
real blue(0:25)
real red(NZ)
real x(NFFT)
complex cx(0:NH)
equivalence (x,cx)
data icos7/2,5,6,0,4,1,3/ !Costas 7x7 pattern
data nc1z/-1/,nc2z/-1/,ng2z/-1/
common/qra64com/ss(NZ,194),s3(0:63,1:63),ccf(NZ,0:25)
@ -29,23 +27,8 @@ subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12,hisgrid_6, &
nsps=6912
istep=nsps/2
nsteps=52*12000/istep - 2
ia=1-istep
savg=0.
df=12000.0/NFFT
do j=1,nsteps
ia=ia+istep
ib=ia+nsps-1
x(1:nsps)=1.2e-4*dd(ia:ib)
x(nsps+1:)=0.0
call four2a(x,nfft,1,-1,0) !r2c FFT
do i=1,NZ
s(i)=real(cx(i))**2 + aimag(cx(i))**2
enddo
ss(1:NZ,j)=s
savg=savg+s
enddo
savg=savg/nsteps
call spec64(dd0,-1,s,savg,ss)
fa=max(nf1,nfqso-ntol)
fb=min(nf2,nfqso+ntol)
ia=nint(fa/df)
@ -70,7 +53,7 @@ subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12,hisgrid_6, &
if(red(if0).gt.sync) then
sync=red(if0)
f0=if0*df
dtx=j*istep/12000.0 - 1.0
! dtx=j*istep/12000.0 - 1.0
i0=if0
j0=j
endif
@ -83,6 +66,23 @@ subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12,hisgrid_6, &
if0=nint(f0/df)
nfreq=nint(f0)
blue(0:25)=ccf(if0,0:25)
dj=0.
if(j0.ge.1 .and. j0.le.24) call peakup(blue(j0-1),blue(j0),blue(j0+1),dj)
xpk=j0 + dj
dtx=xpk*istep/12000.0 - 1.0
i=nint(dj*istep)
if(i.lt.0) then
dd(1-i:NMAX)=dd0(1:NMAX+i)
dd(1:-i)=0.0
else
dd(1:NMAX-i)=dd0(1+i:NMAX)
dd(NMAX-i+1:NMAX)=0.0
endif
! Recompute the symbol spectra, this time aligned for best DT estimate.
ss=0.
call spec64(dd,j0,s,savg,ss)
do i=0,63 !Copy symbol spectra into s3()
k=i0 + 2*i
@ -103,7 +103,6 @@ subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12,hisgrid_6, &
call packcall(mycall,nc1,ltext)
call packcall(hiscall,nc2,ltext)
call packgrid(hisgrid,ng2,ltext)
! call packcall("CQ ",ncq,ltext)
if(nc1.ne.nc1z .or. nc2.ne.nc2z .or. ng2.ne.ng2z) then
do naptype=0,5
@ -134,3 +133,39 @@ subroutine qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12,hisgrid_6, &
return
end subroutine qra64a
subroutine spec64(dd,j0,s,savg,ss)
parameter (NFFT=2*6912,NH=NFFT/2,NZ=5760)
real dd(60*12000)
real s(NZ)
real savg(NZ)
real ss(NZ,194)
real x(NFFT)
complex cx(0:NH)
equivalence (x,cx)
nsps=6912
istep=nsps/2
nsteps=52*12000/istep - 2
ia=1-istep
savg=0.
df=12000.0/NFFT
mj0=mod(j0,2)
do j=1,nsteps
ia=ia+istep
if(j0.ge.0 .and. mod(j,2).eq.mj0) cycle !Skip half of FFTs in 2nd pass
ib=ia+nsps-1
x(1:nsps)=1.2e-4*dd(ia:ib)
x(nsps+1:)=0.0
call four2a(x,nfft,1,-1,0) !r2c FFT
do i=1,NZ
s(i)=real(cx(i))**2 + aimag(cx(i))**2
enddo
ss(1:NZ,j)=s
savg=savg+s
enddo
savg=savg/nsteps
return
end subroutine spec64