WSJT-X/lib/ft4_decode.f90
Steve Franke c26d0b4f29 FT4: Imrovements to sync.
Divide DT search range into 3 segments. Search central segment (near DT=0)
first and try to decode the largest peak. Then find the largest peak in each
of the surrounding segments and try to decode those only if the peak is larger
than the one found in the central segment.

Also re-indent ft4_decode.f90 and some other minor tweaks.
2019-06-16 09:46:33 -05:00

468 lines
17 KiB
Fortran

module ft4_decode
type :: ft4_decoder
procedure(ft4_decode_callback), pointer :: callback
contains
procedure :: decode
end type ft4_decoder
abstract interface
subroutine ft4_decode_callback (this,sync,snr,dt,freq,decoded,nap,qual)
import ft4_decoder
implicit none
class(ft4_decoder), intent(inout) :: this
real, intent(in) :: sync
integer, intent(in) :: snr
real, intent(in) :: dt
real, intent(in) :: freq
character(len=37), intent(in) :: decoded
integer, intent(in) :: nap
real, intent(in) :: qual
end subroutine ft4_decode_callback
end interface
contains
subroutine decode(this,callback,iwave,nQSOProgress,nfqso, &
nutc,nfa,nfb,ndepth,lapcqonly,ncontest,mycall,hiscall)
use timer_module, only: timer
use packjt77
include 'ft4/ft4_params.f90'
class(ft4_decoder), intent(inout) :: this
procedure(ft4_decode_callback) :: callback
parameter (NSS=NSPS/NDOWN,NDMAX=NMAX/NDOWN)
character message*37,msgsent*37
character c77*77
character*37 decodes(100)
character*512 data_dir,fname
character*17 cdatetime0
character*12 mycall,hiscall
character*12 mycall0,hiscall0
character*6 hhmmss
character*4 cqstr,cqstr0
complex cd2(0:NDMAX-1) !Complex waveform
complex cb(0:NDMAX-1)
complex cd(0:NN*NSS-1) !Complex waveform
complex ctwk(2*NSS),ctwk2(2*NSS,-16:16)
real a(5)
real bitmetrics(2*NN,3)
real dd(NMAX)
real llr(2*ND),llra(2*ND),llrb(2*ND),llrc(2*ND),llrd(2*ND)
real candidate(2,100)
real savg(NH1),sbase(NH1)
integer apbits(2*ND)
integer apmy_ru(28),aphis_fd(28)
integer*2 iwave(NMAX) !Raw received data
integer*1 message77(77),rvec(77),apmask(2*ND),cw(2*ND)
integer*1 hbits(2*NN)
integer i4tone(103)
integer nappasses(0:5) ! # of decoding passes for QSO States 0-5
integer naptypes(0:5,4) ! nQSOProgress, decoding pass
integer mcq(29)
integer mrrr(19),m73(19),mrr73(19)
logical nohiscall,unpk77_success
logical first, dobigfft
logical dosubtract,doosd
logical badsync
logical, intent(in) :: lapcqonly
data first/.true./
data mcq/0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0/
data mrrr/0,1,1,1,1,1,1,0,1,0,0,1,0,0,1,0,0,0,1/
data m73/0,1,1,1,1,1,1,0,1,0,0,1,0,1,0,0,0,0,1/
data mrr73/0,1,1,1,1,1,1,0,0,1,1,1,0,1,0,1,0,0,1/
data rvec/0,1,0,0,1,0,1,0,0,1,0,1,1,1,1,0,1,0,0,0,1,0,0,1,1,0,1,1,0, &
1,0,0,1,0,1,1,0,0,0,0,1,0,0,0,1,0,1,0,0,1,1,1,1,0,0,1,0,1, &
0,1,0,1,0,1,1,0,1,1,1,1,1,0,0,0,1,0,1/
save fs,dt,tt,txt,twopi,h,first,apbits,nappasses,naptypes, &
mycall0,hiscall0,cqstr0,ctwk2
this%callback => callback
hhmmss=cdatetime0(8:13)
dxcall13=hiscall
mycall13=mycall
if(first) then
fs=12000.0/NDOWN !Sample rate after downsampling
dt=1/fs !Sample interval after downsample (s)
tt=NSPS*dt !Duration of "itone" symbols (s)
txt=NZ*dt !Transmission length (s) without ramp up/down
twopi=8.0*atan(1.0)
h=1.0
do idf=-16,16
a=0.
a(1)=real(idf)
ctwk=1.
call twkfreq1(ctwk,2*NSS,fs/2.0,a,ctwk2(:,idf))
enddo
mrrr=2*mod(mrrr+rvec(59:77),2)-1
m73=2*mod(m73+rvec(59:77),2)-1
mrr73=2*mod(mrr73+rvec(59:77),2)-1
nappasses(0)=2
nappasses(1)=2
nappasses(2)=2
nappasses(3)=2
nappasses(4)=2
nappasses(5)=3
! iaptype
!------------------------
! 1 CQ ??? ??? (29 ap bits)
! 2 MyCall ??? ??? (29 ap bits)
! 3 MyCall DxCall ??? (58 ap bits)
! 4 MyCall DxCall RRR (77 ap bits)
! 5 MyCall DxCall 73 (77 ap bits)
! 6 MyCall DxCall RR73 (77 ap bits)
!********
naptypes(0,1:4)=(/1,2,0,0/) ! Tx6 selected (CQ)
naptypes(1,1:4)=(/2,3,0,0/) ! Tx1
naptypes(2,1:4)=(/2,3,0,0/) ! Tx2
naptypes(3,1:4)=(/3,6,0,0/) ! Tx3
naptypes(4,1:4)=(/3,6,0,0/) ! Tx4
naptypes(5,1:4)=(/3,1,2,0/) ! Tx5
mycall0=''
hiscall0=''
cqstr0=''
first=.false.
endif
if(cqstr.ne.cqstr0) then
i0=index(cqstr,' ')
if(i0.le.1) then
message='CQ A1AA AA01'
else
message='CQ '//cqstr(1:i0-1)//' A1AA AA01'
endif
i3=-1
n3=-1
call pack77(message,i3,n3,c77)
call unpack77(c77,1,msgsent,unpk77_success)
read(c77,'(29i1)') mcq
mcq=2*mod(mcq+rvec(1:29),2)-1
cqstr0=cqstr
endif
l1=index(mycall,char(0))
if(l1.ne.0) mycall(l1:)=" "
l1=index(hiscall,char(0))
if(l1.ne.0) hiscall(l1:)=" "
if(mycall.ne.mycall0 .or. hiscall.ne.hiscall0) then
apbits=0
apbits(1)=99
apbits(30)=99
apmy_ru=0
aphis_fd=0
if(len(trim(mycall)) .lt. 3) go to 10
nohiscall=.false.
hiscall0=hiscall
if(len(trim(hiscall0)).lt.3) then
hiscall0=mycall ! use mycall for dummy hiscall - mycall won't be hashed.
nohiscall=.true.
endif
message=trim(mycall)//' '//trim(hiscall0)//' RR73'
i3=-1
n3=-1
call pack77(message,i3,n3,c77)
call unpack77(c77,1,msgsent,unpk77_success)
if(i3.ne.1 .or. (message.ne.msgsent) .or. .not.unpk77_success) go to 10
read(c77,'(77i1)') message77
apmy_ru=2*mod(message77(1:28)+rvec(2:29),2)-1
aphis_fd=2*mod(message77(30:57)+rvec(29:56),2)-1
message77=mod(message77+rvec,2)
call encode174_91(message77,cw)
apbits=2*cw-1
if(nohiscall) apbits(30)=99
10 continue
mycall0=mycall
hiscall0=hiscall
endif
maxcand=100
ndecodes=0
decodes=' '
fa=nfa
fb=nfb
dd=iwave
! ndepth=3: 3 passes, bp+osd
! ndepth=2: 3 passes, bp only
! ndepth=1: 1 pass, no subtraction
max_iterations=40
syncmin=1.2
dosubtract=.true.
doosd=.true.
nsp=3
if(ndepth.eq.2) then
doosd=.false.
endif
if(ndepth.eq.1) then
nsp=1
dosubtract=.false.
doosd=.false.
endif
do isp = 1,nsp
if(isp.eq.2) then
if(ndecodes.eq.0) exit
nd1=ndecodes
elseif(isp.eq.3) then
nd2=ndecodes-nd1
if(nd2.eq.0) exit
endif
candidate=0.0
ncand=0
call timer('getcand4',0)
call getcandidates4(dd,fa,fb,syncmin,nfqso,maxcand,savg,candidate, &
ncand,sbase)
call timer('getcand4',1)
dobigfft=.true.
do icand=1,ncand
f0=candidate(1,icand)
snr=candidate(2,icand)-1.0
call timer('ft4_down',0)
call ft4_downsample(dd,dobigfft,f0,cd2) !Downsample to 32 Sam/Sym
call timer('ft4_down',1)
if(dobigfft) dobigfft=.false.
sum2=sum(cd2*conjg(cd2))/(real(NMAX)/real(NDOWN))
if(sum2.gt.0.0) cd2=cd2/sqrt(sum2)
! Sample rate is now 12000/18 = 666.67 samples/second
do iseg=1,3 ! DT search is done over 3 segments
do isync=1,2
if(isync.eq.1) then
idfmin=-12
idfmax=12
idfstp=3
ibmin=-344
ibmax=1012
if(iseg.eq.1) then
ibmin=108
ibmax=560
elseif(iseg.eq.2) then
smax1=smax
ibmin=560
ibmax=1012
elseif(iseg.eq.3) then
ibmin=-344
ibmax=108
endif
ibstp=4
else
idfmin=idfbest-4
idfmax=idfbest+4
idfstp=1
ibmin=ibest-5
ibmax=ibest+5
ibstp=1
endif
ibest=-1
idfbest=0
smax=-99.
call timer('sync4d ',0)
do idf=idfmin,idfmax,idfstp
do istart=ibmin,ibmax,ibstp
call sync4d(cd2,istart,ctwk2(:,idf),1,sync) !Find sync power
if(sync.gt.smax) then
smax=sync
ibest=istart
idfbest=idf
endif
enddo
enddo
call timer('sync4d ',1)
enddo
if(iseg.eq.1) smax1=smax
if(smax.lt.0.7) cycle
if(iseg.gt.1 .and. smax.lt.smax1) cycle
f1=f0+real(idfbest)
if( f1.le.10.0 .or. f1.ge.4990.0 ) cycle
call timer('ft4down ',0)
call ft4_downsample(dd,dobigfft,f1,cb) !Final downsample, corrected f0
call timer('ft4down ',1)
sum2=sum(abs(cb)**2)/(real(NSS)*NN)
if(sum2.gt.0.0) cb=cb/sqrt(sum2)
cd=0.
if(ibest.ge.0) then
it=min(NDMAX-1,ibest+NN*NSS-1)
np=it-ibest+1
cd(0:np-1)=cb(ibest:it)
else
cd(-ibest:ibest+NN*NSS-1)=cb(0:NN*NSS+2*ibest-1)
endif
call timer('bitmet ',0)
call get_ft4_bitmetrics(cd,bitmetrics,badsync)
call timer('bitmet ',1)
if(badsync) cycle
hbits=0
where(bitmetrics(:,1).ge.0) hbits=1
ns1=count(hbits( 1: 8).eq.(/0,0,0,1,1,0,1,1/))
ns2=count(hbits( 67: 74).eq.(/0,1,0,0,1,1,1,0/))
ns3=count(hbits(133:140).eq.(/1,1,1,0,0,1,0,0/))
ns4=count(hbits(199:206).eq.(/1,0,1,1,0,0,0,1/))
nsync_qual=ns1+ns2+ns3+ns4
if(nsync_qual.lt. 20) cycle
scalefac=2.83
llra( 1: 58)=bitmetrics( 9: 66, 1)
llra( 59:116)=bitmetrics( 75:132, 1)
llra(117:174)=bitmetrics(141:198, 1)
llra=scalefac*llra
llrb( 1: 58)=bitmetrics( 9: 66, 2)
llrb( 59:116)=bitmetrics( 75:132, 2)
llrb(117:174)=bitmetrics(141:198, 2)
llrb=scalefac*llrb
llrc( 1: 58)=bitmetrics( 9: 66, 3)
llrc( 59:116)=bitmetrics( 75:132, 3)
llrc(117:174)=bitmetrics(141:198, 3)
llrc=scalefac*llrc
apmag=maxval(abs(llra))*1.1
npasses=3+nappasses(nQSOProgress)
if(lapcqonly) npasses=4
if(ndepth.eq.1) npasses=3
if(ncontest.ge.5) npasses=3 ! Don't support Fox and Hound
do ipass=1,npasses
if(ipass.eq.1) llr=llra
if(ipass.eq.2) llr=llrb
if(ipass.eq.3) llr=llrc
if(ipass.le.3) then
apmask=0
iaptype=0
endif
if(ipass .gt. 3) then
llrd=llra
iaptype=naptypes(nQSOProgress,ipass-3)
if(lapcqonly) iaptype=1
! ncontest=0 : NONE
! 1 : NA_VHF
! 2 : EU_VHF
! 3 : FIELD DAY
! 4 : RTTY
! 5 : FOX
! 6 : HOUND
!
! Conditions that cause us to bail out of AP decoding
napwid=50
if(ncontest.le.4 .and. iaptype.ge.3 .and. (abs(f1-nfqso).gt.napwid) ) cycle
if(iaptype.ge.2 .and. apbits(1).gt.1) cycle ! No, or nonstandard, mycall
if(iaptype.ge.3 .and. apbits(30).gt.1) cycle ! No, or nonstandard, dxcall
if(iaptype.eq.1) then ! CQ or CQ TEST or CQ FD or CQ RU or CQ SCC
apmask=0
apmask(1:29)=1
llrd(1:29)=apmag*mcq(1:29)
endif
if(iaptype.eq.2) then ! MyCall,???,???
apmask=0
if(ncontest.eq.0.or.ncontest.eq.1) then
apmask(1:29)=1
llrd(1:29)=apmag*apbits(1:29)
else if(ncontest.eq.2) then
apmask(1:28)=1
llrd(1:28)=apmag*apbits(1:28)
else if(ncontest.eq.3) then
apmask(1:28)=1
llrd(1:28)=apmag*apbits(1:28)
else if(ncontest.eq.4) then
apmask(2:29)=1
llrd(2:29)=apmag*apmy_ru(1:28)
endif
endif
if(iaptype.eq.3) then ! MyCall,DxCall,???
apmask=0
if(ncontest.eq.0.or.ncontest.eq.1.or.ncontest.eq.2) then
apmask(1:58)=1
llrd(1:58)=apmag*apbits(1:58)
else if(ncontest.eq.3) then ! Field Day
apmask(1:56)=1
llrd(1:28)=apmag*apbits(1:28)
llrd(29:56)=apmag*aphis_fd(1:28)
else if(ncontest.eq.4) then ! RTTY RU
apmask(2:57)=1
llrd(2:29)=apmag*apmy_ru(1:28)
llrd(30:57)=apmag*apbits(30:57)
endif
endif
if(iaptype.eq.4 .or. iaptype.eq.5 .or. iaptype.eq.6) then
apmask=0
if(ncontest.le.4) then
apmask(1:91)=1 ! mycall, hiscall, RRR|73|RR73
if(iaptype.eq.6) llrd(1:91)=apmag*apbits(1:91)
endif
endif
llr=llrd
endif
message77=0
dmin=0.0
call timer('bpdec174',0)
call bpdecode174_91(llr,apmask,max_iterations,message77, &
cw,nharderror,niterations)
call timer('bpdec174',1)
if(doosd .and. nharderror.lt.0) then
ndeep=3
! if(abs(nfqso-f1).le.napwid) then
! ndeep=4
! endif
call timer('osd174_91 ',0)
call osd174_91(llr,apmask,ndeep,message77,cw,nharderror,dmin)
call timer('osd174_91 ',1)
endif
if(sum(message77).eq.0) cycle
if( nharderror.ge.0 ) then
message77=mod(message77+rvec,2) ! remove rvec scrambling
write(c77,'(77i1)') message77(1:77)
call unpack77(c77,1,message,unpk77_success)
if(unpk77_success.and.dosubtract) then
call get_ft4_tones_from_77bits(message77,i4tone)
dt=real(ibest)/666.67
call timer('subtract',0)
call subtractft4(dd,i4tone,f1,dt)
call timer('subtract',1)
endif
idupe=0
do i=1,ndecodes
if(decodes(i).eq.message) idupe=1
enddo
if(idupe.eq.1) exit
ndecodes=ndecodes+1
decodes(ndecodes)=message
if(snr.gt.0.0) then
xsnr=10*log10(snr)-14.8
else
xsnr=-21.0
endif
nsnr=nint(max(-21.0,xsnr))
xdt=ibest/666.67 - 0.5
!write(21,'(i6.6,i5,2x,f4.1,i6,2x,a37,2x,f4.1,3i3,f5.1,i4,i4,i4)') &
! nutc,nsnr,xdt,nint(f1),message,smax,iaptype,ipass,isp,dmin,nsync_qual,nharderror,iseg
call this%callback(smax,nsnr,xdt,f1,message,iaptype,qual)
exit
endif
enddo !Sequence estimation
if(nharderror.ge.0) exit
enddo !3 DT segments
enddo !Candidate list
enddo !Subtraction loop
return
end subroutine decode
end module ft4_decode