WSJT-X/lib/jt65_decode.f90

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Fortran
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module jt65_decode
integer, parameter :: NSZ=3413, NZMAX=60*12000
type :: jt65_decoder
procedure(jt65_decode_callback), pointer :: callback => null()
contains
procedure :: decode
end type jt65_decoder
! Callback function to be called with each decode
abstract interface
subroutine jt65_decode_callback(this,sync,snr,dt,freq,drift, &
nflip,width,decoded,ft,qual,nsmo,nsum,minsync)
import jt65_decoder
implicit none
class(jt65_decoder), intent(inout) :: this
real, intent(in) :: sync
integer, intent(in) :: snr
real, intent(in) :: dt
integer, intent(in) :: freq
integer, intent(in) :: drift
integer, intent(in) :: nflip
real, intent(in) :: width
character(len=22), intent(in) :: decoded
integer, intent(in) :: ft
integer, intent(in) :: qual
integer, intent(in) :: nsmo
integer, intent(in) :: nsum
integer, intent(in) :: minsync
end subroutine jt65_decode_callback
end interface
contains
subroutine decode(this,callback,dd0,npts,newdat,nutc,nf1,nf2,nfqso, &
ntol,nsubmode,minsync,nagain,n2pass,nrobust,ntrials,naggressive, &
ndepth,clearave,mycall,hiscall,hisgrid,nexp_decode)
! Process dd0() data to find and decode JT65 signals.
use jt65_mod
use timer_module, only: timer
include 'constants.f90'
class(jt65_decoder), intent(inout) :: this
procedure(jt65_decode_callback) :: callback
real, intent(in) :: dd0(NZMAX)
integer, intent(in) :: npts, nutc, nf1, nf2, nfqso, ntol &
, nsubmode, minsync, n2pass, ntrials, naggressive, ndepth &
, nexp_decode
logical, intent(in) :: newdat, nagain, nrobust, clearave
character(len=12), intent(in) :: mycall, hiscall
character(len=6), intent(in) :: hisgrid
real dd(NZMAX)
real ss(322,NSZ)
real savg(NSZ)
real a(5)
character*22 decoded,decoded0,avemsg,deepave
type candidate
real freq
real dt
real sync
real flip
end type candidate
type(candidate) ca(300)
type accepted_decode
real freq
real dt
real sync
character*22 decoded
end type accepted_decode
type(accepted_decode) dec(50)
logical :: first_time,prtavg,single_decode,bVHF
integer h0(0:11),d0(0:11)
real r0(0:11)
common/decstats/ntry65a,ntry65b,n65a,n65b,num9,numfano
common/steve/thresh0
! 0 1 2 3 4 5 6 7 8 9 10 11
data h0/41,42,43,43,44,45,46,47,48,48,49,49/
data d0/71,72,73,74,76,77,78,80,81,82,83,83/
! 0 1 2 3 4 5 6 7 8 9 10 11
data r0/0.70,0.72,0.74,0.76,0.78,0.80,0.82,0.84,0.86,0.88,0.90,0.90/
data nutc0/-999/,nfreq0/-999/,nsave/0/
save
this%callback => callback
first_time=newdat
dd=dd0
ndecoded=0
if(nsubmode.ge.100) then
! This is QRA64 mode
mode64=2**(nsubmode-100)
call qra64a(dd,nutc,nf1,nf2,nfqso,ntol,mode64,mycall,hiscall, &
hisgrid,sync,nsnr,dtx,nfreq,decoded,nft)
if (associated(this%callback)) then
ndrift=0
nflip=1
width=1.0
nsmo=0
nqual=0
call this%callback(sync,nsnr,dtx,nfreq,ndrift, &
nflip,width,decoded,nft,nqual,nsmo,1,minsync)
end if
go to 900
endif
do ipass=1,n2pass !Two-pass decoding loop
first_time=.true.
if(ipass.eq.1) then !First-pass parameters
thresh0=2.5
nsubtract=1
elseif( ipass.eq.2 ) then !Second-pass parameters
thresh0=2.5
nsubtract=0
endif
if(n2pass.lt.2) nsubtract=0
! if(newdat) then
call timer('symsp65 ',0)
ss=0.
call symspec65(dd,npts,ss,nhsym,savg) !Get normalized symbol spectra
call timer('symsp65 ',1)
! endif
nfa=nf1
nfb=nf2
single_decode=iand(nexp_decode,32).ne.0
bVHF=iand(nexp_decode,64).ne.0
!### Q: should either of the next two uses of "single_decode" be "bVHF" instead?
if(single_decode .or. (bVHF .and. ntol.lt.1000)) then
nfa=max(200,nfqso-ntol)
nfb=min(4000,nfqso+ntol)
thresh0=1.0
endif
df=12000.0/8192.0 !df = 1.465 Hz
if(bVHF) then
ia=max(1,nint(nfa/df)-ntol)
ib=min(NSZ,nint(nfb/df)+ntol)
nz=ib-ia+1
call lorentzian(savg(ia),nz,a)
baseline=a(1)
amp=a(2)
f0=(a(3)+ia-1)*df
width=a(4)*df
endif
ncand=0
call timer('sync65 ',0)
call sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,0,bVHF)
call timer('sync65 ',1)
! If a candidate was found within +/- ntol of nfqso, move it into ca(1).
call fqso_first(nfqso,ntol,ca,ncand)
if(single_decode) then
if(ncand.eq.0) ncand=1
if(abs(ca(1)%freq - f0).gt.width) width=2*df !### ??? ###
endif
nvec=ntrials
if(ncand.gt.75) then
nvec=100
endif
mode65=2**nsubmode
nflip=1
nqd=0
decoded=' '
decoded0=""
freq0=0.
prtavg=.false.
if(.not.nagain) nsum=0
if(clearave) then
nsum=0
nsave=0
endif
if(bVHF) then
! Be sure to search for shorthand message at nfqso +/- ntol
if(ncand.lt.300) ncand=ncand+1
ca(ncand)%sync=5.0
ca(ncand)%dt=2.5
ca(ncand)%freq=nfqso
endif
do icand=1,ncand
sync1=ca(icand)%sync
dtx=ca(icand)%dt
freq=ca(icand)%freq
if(bVHF) then
flip=ca(icand)%flip
nflip=flip
endif
if(sync1.lt.float(minsync)) nflip=0
if(ipass.eq.1) ntry65a=ntry65a + 1
if(ipass.eq.2) ntry65b=ntry65b + 1
call timer('decod65a',0)
nft=0
nspecial=0
call decode65a(dd,npts,first_time,nqd,freq,nflip,mode65,nvec, &
naggressive,ndepth,ntol,mycall,hiscall,hisgrid, &
nexp_decode,bVHF,sync2,a,dtx,nft,nspecial,qual, &
nhist,nsmo,decoded)
if(nspecial.eq.2) decoded='RO'
if(nspecial.eq.3) decoded='RRR'
if(nspecial.eq.4) decoded='73'
call timer('decod65a',1)
if(sync1.lt.float(minsync) .and. &
decoded.eq.' ') nflip=0
if(nft.ne.0) nsum=1
nhard_min=param(1)
nrtt1000=param(4)
ntotal_min=param(5)
nsmo=param(9)
nfreq=nint(freq+a(1))
ndrift=nint(2.0*a(2))
if(bVHF) then
s2db=sync1 - 30.0 + db(width/3.3) !### VHF/UHF/microwave
if(nspecial.gt.0) s2db=sync2
else
s2db=10.0*log10(sync2) - 35 !### Empirical (HF)
endif
nsnr=nint(s2db)
if(nsnr.lt.-30) nsnr=-30
if(nsnr.gt.-1) nsnr=-1
nftt=0
if(nft.ne.1 .and. iand(ndepth,16).eq.16 .and. (.not.prtavg)) then
! Single-sequence FT decode failed, so try for an average FT decode.
if(nutc.ne.nutc0 .or. abs(nfreq-nfreq0).gt.ntol) then
! This is a new minute or a new frequency, so call avg65.
nutc0=nutc
nfreq0=nfreq
nsave=nsave+1
nsave=mod(nsave-1,64)+1
call avg65(nutc,nsave,sync1,dtx,nflip,nfreq,mode65,ntol, &
ndepth,nagain,ntrials,naggressive,clearave,neme,mycall, &
hiscall,hisgrid,nftt,avemsg,qave,deepave,nsum,ndeepave)
nsmo=param(9)
nqave=qave
if (associated(this%callback) .and. nsum.ge.2) then
call this%callback(sync1,nsnr,dtx-1.0,nfreq,ndrift, &
nflip,width,avemsg,nftt,nqave,nsmo,nsum,minsync)
prtavg=.true.
end if
endif
endif
if(nftt.eq.1) then
! nft=1
decoded=avemsg
go to 5
endif
n=naggressive
rtt=0.001*nrtt1000
if(nft.lt.2 .and. minsync.ge.0 .and. nspecial.eq.0) then
if(nhard_min.gt.50) cycle
if(nhard_min.gt.h0(n)) cycle
if(ntotal_min.gt.d0(n)) cycle
if(rtt.gt.r0(n)) cycle
endif
5 continue
if(decoded.eq.decoded0 .and. abs(freq-freq0).lt. 3.0 .and. &
minsync.ge.0) cycle !Don't display dupes
if(decoded.ne.' ' .or. minsync.lt.0) then
if(nsubtract.eq.1) then
call timer('subtr65 ',0)
call subtract65(dd,npts,freq,dtx)
call timer('subtr65 ',1)
endif
ndupe=0 ! de-dedupe
do i=1, ndecoded
if(decoded==dec(i)%decoded) then
ndupe=1
exit
endif
enddo
if(ndupe.ne.1 .and. sync1.ge.float(minsync)) then
if(ipass.eq.1) n65a=n65a + 1
if(ipass.eq.2) n65b=n65b + 1
if(ndecoded.lt.50) ndecoded=ndecoded+1
dec(ndecoded)%freq=freq+a(1)
dec(ndecoded)%dt=dtx
dec(ndecoded)%sync=sync2
dec(ndecoded)%decoded=decoded
nqual=min(qual,9999.0)
if (associated(this%callback)) then
call this%callback(sync1,nsnr,dtx-1.0,nfreq,ndrift, &
nflip,width,decoded,nft,nqual,nsmo,1,minsync)
end if
endif
decoded0=decoded
freq0=freq
if(decoded0.eq.' ') decoded0='*'
endif
enddo !Candidate loop
if(ndecoded.lt.1) exit
enddo !Two-pass loop
900 return
end subroutine decode
subroutine avg65(nutc,nsave,snrsync,dtxx,nflip,nfreq,mode65,ntol,ndepth, &
nagain, ntrials,naggressive,clearave,neme,mycall,hiscall,hisgrid,nftt, &
avemsg,qave,deepave,nsum,ndeepave)
! Decodes averaged JT65 data
use jt65_mod
parameter (MAXAVE=64)
character*22 avemsg,deepave,deepbest
character mycall*12,hiscall*12,hisgrid*6
character*1 csync,cused(64)
logical nagain
integer iused(64)
! Accumulated data for message averaging
integer iutc(MAXAVE)
integer nfsave(MAXAVE)
integer nflipsave(MAXAVE)
real s1b(-255:256,126)
real s1save(-255:256,126,MAXAVE)
real s2(66,126)
real s3save(64,63,MAXAVE)
real s3b(64,63)
real s3c(64,63)
real dtsave(MAXAVE)
real syncsave(MAXAVE)
logical first,clearave
data first/.true./
save
if(first .or. clearave) then
iutc=-1
nfsave=0
dtdiff=0.2
first=.false.
s3save=0.
s1save=0.
nsave=1 !### ???
! Silence compiler warnings
if(nagain .and. ndeepave.eq.-99 .and. neme.eq.-99) stop
endif
do i=1,64
if(iutc(i).lt.0) exit
if(nutc.eq.iutc(i) .and. abs(nfreq-nfsave(i)).le.ntol) go to 10
enddo
! Save data for message averaging
iutc(nsave)=nutc
syncsave(nsave)=snrsync
dtsave(nsave)=dtxx
nfsave(nsave)=nfreq
nflipsave(nsave)=nflip
s1save(-255:256,1:126,nsave)=s1
s3save(1:64,1:63,nsave)=s3a
10 syncsum=0.
dtsum=0.
nfsum=0
nsum=0
s1b=0.
s3b=0.
s3c=0.
do i=1,MAXAVE !Consider all saved spectra
cused(i)='.'
if(iutc(i).lt.0) cycle
if(mod(iutc(i),2).ne.mod(nutc,2)) cycle !Use only same (odd/even) seq
if(abs(dtxx-dtsave(i)).gt.dtdiff) cycle !DT must match
if(abs(nfreq-nfsave(i)).gt.ntol) cycle !Freq must match
if(nflip.ne.nflipsave(i)) cycle !Sync type (*/#) must match
s3b=s3b + s3save(1:64,1:63,i)
s1b=s1b + s1save(-255:256,1:126,i)
syncsum=syncsum + syncsave(i)
dtsum=dtsum + dtsave(i)
nfsum=nfsum + nfsave(i)
cused(i)='$'
nsum=nsum+1
iused(nsum)=i
enddo
if(nsum.lt.64) iused(nsum+1)=0
syncave=0.
dtave=0.
fave=0.
if(nsum.gt.0) then
syncave=syncsum/nsum
dtave=dtsum/nsum
fave=float(nfsum)/nsum
endif
do i=1,nsave
csync='*'
if(nflipsave(i).lt.0.0) csync='#'
write(14,1000) cused(i),iutc(i),syncsave(i),dtsave(i)-1.0,nfsave(i),csync
1000 format(a1,i5.4,f6.1,f6.2,i6,1x,a1)
enddo
if(nsum.lt.2) go to 900
nftt=0
df=1378.125/512.0
! Do the smoothing loop
qualbest=0.
minsmo=0
maxsmo=0
if(mode65.ge.2) then
minsmo=nint(width/df)
maxsmo=2*minsmo
endif
nn=0
do ismo=minsmo,maxsmo
if(ismo.gt.0) then
do j=1,126
call smo121(s1b(-255,j),512)
if(j.eq.1) nn=nn+1
if(nn.ge.4) then
call smo121(s1b(-255,j),512)
if(j.eq.1) nn=nn+1
endif
enddo
endif
do i=1,66
jj=i
if(mode65.eq.2) jj=2*i-1
if(mode65.eq.4) then
ff=4*(i-1)*df - 355.297852
jj=nint(ff/df)+1
endif
s2(i,1:126)=s1b(jj,1:126)
enddo
do j=1,63
k=mdat(j) !Points to data symbol
if(nflip.lt.0) k=mdat2(j)
do i=1,64
s3c(i,j)=4.e-5*s2(i+2,k)
enddo
enddo
nadd=nsum*ismo
call extract(s3c,nadd,mode65,ntrials,naggressive,ndepth,nflip,mycall, &
hiscall,hisgrid,nexp_decode,ncount,nhist,avemsg,ltext,nftt,qual)
if(nftt.eq.1) then
nsmo=ismo
param(9)=nsmo
go to 900
else if(nftt.eq.2) then
if(qual.gt.qualbest) then
deepbest=avemsg
qualbest=qual
nnbest=nn
nsmobest=ismo
nfttbest=nftt
endif
endif
enddo
if(nfttbest.eq.2) then
avemsg=deepbest !### ???
deepave=deepbest
qave=qualbest
nsmo=nsmobest
param(9)=nsmo
nftt=nfttbest
endif
900 continue
return
end subroutine avg65
end module jt65_decode