WSJT-X/lib/ft8_decode.f90
Steven Franke d8f9f385b4 Use quarter-symbol steps for time sync. Lower sync threshold. Implement subtraction and two pass decoding. Use osd2 only near nfqso.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7861 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2017-07-12 21:49:39 +00:00

118 lines
3.3 KiB
Fortran

module ft8_decode
type :: ft8_decoder
procedure(ft8_decode_callback), pointer :: callback
contains
procedure :: decode
end type ft8_decoder
abstract interface
subroutine ft8_decode_callback (this,sync,snr,dt,freq,nbadcrc,decoded)
import ft8_decoder
implicit none
class(ft8_decoder), intent(inout) :: this
real, intent(in) :: sync
integer, intent(in) :: snr
real, intent(in) :: dt
real, intent(in) :: freq
integer, intent(in) :: nbadcrc
character(len=22), intent(in) :: decoded
end subroutine ft8_decode_callback
end interface
contains
subroutine decode(this,callback,iwave,nfqso,newdat,nutc,nfa, &
nfb,nagain,ndepth,nsubmode,mycall12,hiscall12,hisgrid6)
! use wavhdr
use timer_module, only: timer
include 'fsk4hf/ft8_params.f90'
! type(hdr) h
class(ft8_decoder), intent(inout) :: this
procedure(ft8_decode_callback) :: callback
real s(NH1,NHSYM)
real candidate(3,200)
real dd(15*12000)
logical, intent(in) :: nagain
logical newdat,lsubtract
character*12 mycall12, hiscall12
character*6 hisgrid6
integer*2 iwave(15*12000)
integer apsym(KK)
character datetime*13,message*22
save s,dd
this%callback => callback
write(datetime,1001) nutc !### TEMPORARY ###
1001 format("000000_",i6.6)
if(index(hisgrid6," ").eq.0) hisgrid6="EN50"
call ft8apset(mycall12,hiscall12,hisgrid6,apsym)
dd=iwave
! For now:
! ndepth=1: no subtraction, 1 pass, belief propagation only
! ndepth=2: subtraction, 2 passes, belief propagation only
! ndepth=3: subtraction, 2 passes, bp+osd2 at and near nfqso
if(ndepth.eq.1) npass=1
if(ndepth.ge.2) npass=2
do ipass=1,npass
newdat=.true. ! Is this a problem? I hijacked newdat.
if(ipass.eq.1) then
lsubtract=.true.
if(ndepth.eq.1) lsubtract=.false.
syncmin=1.3
else
lsubtract=.false.
syncmin=1.3
endif
call timer('sync8 ',0)
call sync8(dd,nfa,nfb,syncmin,nfqso,s,candidate,ncand)
call timer('sync8 ',1)
do icand=1,ncand
sync=candidate(3,icand)
f1=candidate(1,icand)
xdt=candidate(2,icand)
nsnr0=min(99,nint(10.0*log10(sync) - 25.5)) !### empirical ###
call timer('ft8b ',0)
call ft8b(dd,newdat,nfqso,ndepth,lsubtract,icand,sync,f1,xdt,apsym,nharderrors, &
dmin,nbadcrc,iap,ipass,message,xsnr)
nsnr=xsnr
xdt=xdt-0.6
call timer('ft8b ',1)
if (associated(this%callback)) call this%callback(sync,nsnr,xdt, &
f1,nbadcrc,message)
enddo
! h=default_header(12000,NMAX)
! open(10,file='subtract.wav',status='unknown',access='stream')
! iwave=nint(dd)
! write(10) h,iwave
! close(10)
enddo
return
end subroutine decode
end module ft8_decode
subroutine ft8apset(mycall12,hiscall12,hisgrid6,apsym)
parameter(NAPM=4,KK=87)
character*12 mycall12,hiscall12
character*22 msg,msgsent
character*6 mycall,hiscall
character*6 hisgrid6
character*4 hisgrid
integer apsym(KK)
integer*1 msgbits(KK)
integer itone(KK)
mycall=mycall12(1:6)
hiscall=hiscall12(1:6)
hisgrid=hisgrid6(1:4)
msg=mycall//' '//hiscall//' '//hisgrid
call genft8(msg,msgsent,msgbits,itone)
apsym=2*msgbits-1
return
end subroutine ft8apset