WSJT-X/lib/fsk4hf/ft2d.f90

336 lines
9.4 KiB
Fortran
Raw Normal View History

program ft2d
use crc
use packjt77
include 'ft2_params.f90'
character arg*8,message*37,c77*77,infile*80,fname*16,datetime*11
character*37 decodes(100)
character*120 data_dir
character*90 dmsg
complex c2(0:NMAX/16-1) !Complex waveform
complex cb(0:NMAX/16-1)
complex cd(0:144*10-1) !Complex waveform
complex c1(0:9),c0(0:9)
complex ccor(0:1,144)
complex csum,cterm,cc0,cc1,csync1,csync2
complex csync(16),csl(0:159)
real*8 fMHz
real a(5)
real rxdata(128),llr(128) !Soft symbols
real llr2(128)
real sbits(144),sbits1(144),sbits3(144)
real ps(0:8191),psbest(0:8191)
real candidates(100,2)
real savg(NH1),sbase(NH1)
integer ihdr(11)
integer*2 iwave(NMAX) !Generated full-length waveform
integer*1 message77(77),apmask(128),cw(128)
integer*1 hbits(144),hbits1(144),hbits3(144)
integer*1 s16(16),s45(45)
logical unpk77_success
data s16/0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0/
data s45/0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1,0,0,1,1,1,1,0,0,1,0,0,0,1,1,0,1,0,0,0,1,1,1,0,0/
fs=12000.0/NDOWN !Sample rate
dt=1/fs !Sample interval after downsample (s)
tt=NSPS*dt !Duration of "itone" symbols (s)
baud=1.0/tt !Keying rate for "itone" symbols (baud)
txt=NZ*dt !Transmission length (s)
twopi=8.0*atan(1.0)
h=0.800 !h=0.8 seems to be optimum for AWGN sensitivity (not for fading)
dphi=twopi/2*baud*h*dt*16 ! dt*16 is samp interval after downsample
dphi0=-1*dphi
dphi1=+1*dphi
phi0=0.0
phi1=0.0
do i=0,9
c1(i)=cmplx(cos(phi1),sin(phi1))
c0(i)=cmplx(cos(phi0),sin(phi0))
phi1=mod(phi1+dphi1,twopi)
phi0=mod(phi0+dphi0,twopi)
enddo
the=twopi*h/2.0
cc1=cmplx(cos(the),-sin(the))
cc0=cmplx(cos(the),sin(the))
k=0
do j=1,16
dphi1=(2*s16(j)-1)*dphi
phi1=0.0
do i=0,9
csl(k)=cmplx(cos(phi1),sin(phi1))
phi1=mod(phi1+dphi1,twopi)
k=k+1
enddo
enddo
nargs=iargc()
if(nargs.lt.1) then
print*,'Usage: ft2d [-a <data_dir>] [-f fMHz] file1 [file2 ...]'
go to 999
endif
iarg=1
data_dir="."
call getarg(iarg,arg)
if(arg(1:2).eq.'-a') then
call getarg(iarg+1,data_dir)
iarg=iarg+2
endif
call getarg(iarg,arg)
if(arg(1:2).eq.'-f') then
call getarg(iarg+1,arg)
read(arg,*) fMHz
iarg=iarg+2
endif
ncoh=1
do ifile=iarg,nargs
call getarg(ifile,infile)
j2=index(infile,'.wav')
open(10,file=infile,status='old',access='stream')
read(10,end=999) ihdr,iwave
read(infile(j2-4:j2-1),*) nutc
datetime=infile(j2-11:j2-1)
close(10)
candidates=0.0
ncand=0
call getcandidates2(iwave,375.0,3000.0,0.2,2200.0,100,savg,candidates,ncand,sbase)
ndecodes=0
do icand=1,ncand
f0=candidates(icand,1)
xsnr=1.0
if( f0.le.375.0 .or. f0.ge.(5000.0-375.0) ) cycle
call ft2_downsample(iwave,f0,c2) ! downsample from 160s/Symbol to 10s/Symbol
!c2=c2/sqrt(sum(abs(c2(0:NMAX/16-1))))
!ishift=-1
!rccbest=-99.
!do is=0,435
!rcc=0.0
! do id=10,10
! rcc=rcc+abs(sum(conjg(c2(is:is+159-id))*c2(is+id:is+159)*csl(0:159-id)*conjg(csl(id:159))))
! enddo
! if(rcc.gt.rccbest) then
! rccbest=rcc
! ishift=is
! endif
!write(21,*) is,rcc
!enddo
! 750 samples/second here
ibest=-1
sybest=-99.
dfbest=-1.
do if=-30,+30
df=if
a=0.
a(1)=-df
call twkfreq1(c2,NMAX/16,fs,a,cb)
do is=0,374
csync1=0.
cterm=1
do ib=1,16
! do ib=1,45
i1=(ib-1)*10+is
if(s16(ib).eq.1) then
! if(s45(ib).eq.1) then
csync1=csync1+sum(cb(i1:i1+9)*conjg(c1(0:9)))*cterm
cterm=cterm*cc1
else
csync1=csync1+sum(cb(i1:i1+9)*conjg(c0(0:9)))*cterm
cterm=cterm*cc0
endif
enddo
if(abs(csync1).gt.sybest) then
ibest=is
sybest=abs(csync1)
dfbest=df
endif
enddo
enddo
a=0.
!dfbest=1500.0-f0
a(1)=-dfbest
call twkfreq1(c2,NMAX/16,fs,a,cb)
!ibest=197
ib=ibest
cd=cb(ib:ib+144*10-1)
s2=sum(cd*conjg(cd))/(10*144)
cd=cd/sqrt(s2)
do nseq=1,4
if( nseq.eq.1 ) then ! noncoherent single-symbol detection
sbits1=0.0
do ibit=1,144
ib=(ibit-1)*10
ccor(1,ibit)=sum(cd(ib:ib+9)*conjg(c1(0:9)))
ccor(0,ibit)=sum(cd(ib:ib+9)*conjg(c0(0:9)))
sbits1(ibit)=abs(ccor(1,ibit))-abs(ccor(0,ibit))
hbits1(ibit)=0
if(sbits1(ibit).gt.0) hbits1(ibit)=1
enddo
sbits=sbits1
hbits=hbits1
sbits3=sbits1
hbits3=hbits1
elseif( nseq.ge.2 ) then
nbit=2*nseq-1
numseq=2**(nbit)
ps=0
do ibit=nbit/2+1,144-nbit/2
ps=0.0
pmax=0.0
do iseq=0,numseq-1
csum=0.0
cterm=1.0
k=1
do i=nbit-1,0,-1
ibb=iand(iseq/(2**i),1)
csum=csum+ccor(ibb,ibit-(nbit/2+1)+k)*cterm
if(ibb.eq.0) cterm=cterm*cc0
if(ibb.eq.1) cterm=cterm*cc1
k=k+1
enddo
ps(iseq)=abs(csum)
if( ps(iseq) .gt. pmax ) then
pmax=ps(iseq)
ibflag=1
endif
enddo
if( ibflag .eq. 1 ) then
psbest=ps
ibflag=0
endif
call getbitmetric(2**(nbit/2),psbest,numseq,sbits3(ibit))
hbits3(ibit)=0
if(sbits3(ibit).gt.0) hbits3(ibit)=1
enddo
sbits=sbits3
hbits=hbits3
endif
nsync_qual=count(hbits(1:16).eq.s16)
! if(nsync_qual.lt.10) exit
rxdata=sbits(17:144)
rxav=sum(rxdata(1:128))/128.0
rx2av=sum(rxdata(1:128)*rxdata(1:128))/128.0
rxsig=sqrt(rx2av-rxav*rxav)
rxdata=rxdata/rxsig
sigma=0.80
llr(1:128)=2*rxdata/(sigma*sigma)
!xllrmax=maxval(abs(llr))
!write(*,*) ifile,icand,nseq,nsync_qual
apmask=0
!apmask(1:29)=1
!llr(1:29)=xllrmax*(2*s45(17:45)-1)
max_iterations=40
do ibias=0,0
llr2=llr
if(ibias.eq.1) llr2=llr+0.4
if(ibias.eq.2) llr2=llr-0.4
call bpdecode128_90(llr2,apmask,max_iterations,message77,cw,nharderror,niterations)
if(nharderror.ge.0) exit
enddo
if(sum(message77).eq.0) cycle
if( nharderror.ge.0 ) then
write(c77,'(77i1)') message77(1:77)
2019-01-16 15:55:01 -05:00
call unpack77(c77,1,message,unpk77_success)
idupe=0
do i=1,ndecodes
if(decodes(i).eq.message) idupe=1
enddo
if(idupe.eq.1) goto 888
ndecodes=ndecodes+1
decodes(ndecodes)=message
nsnr=nint(xsnr)
freq=f0+dfbest
1210 format(a11,2i4,f6.2,f12.7,2x,a22,i3)
write(*,1212) datetime(8:11),nsnr,ibest/750.0,freq,message,'*',nseq,nharderror,nsync_qual
1212 format(a4,i4,2x,f5.3,f11.1,2x,a22,a1,i5,i5,i5)
goto 888
endif
enddo ! nseq
888 continue
enddo !candidate list
enddo !files
write(*,1120)
1120 format("<DecodeFinished>")
999 end program ft2d
subroutine getbitmetric(ib,ps,ns,xmet)
real ps(0:ns-1)
xm1=0
xm0=0
do i=0,ns-1
if( iand(i/ib,1) .eq. 1 .and. ps(i) .gt. xm1 ) xm1=ps(i)
if( iand(i/ib,1) .eq. 0 .and. ps(i) .gt. xm0 ) xm0=ps(i)
enddo
xmet=xm1-xm0
return
end subroutine getbitmetric
subroutine downsample2(ci,f0,co)
parameter(NI=144*160,NH=NI/2,NO=NI/16) ! downsample from 200 samples per symbol to 10
complex ci(0:NI-1),ct(0:NI-1)
complex co(0:NO-1)
fs=12000.0
df=fs/NI
ct=ci
call four2a(ct,NI,1,-1,1) !c2c FFT to freq domain
i0=nint(f0/df)
ct=cshift(ct,i0)
co=0.0
co(0)=ct(0)
b=8.0
do i=1,NO/2
arg=(i*df/b)**2
filt=exp(-arg)
co(i)=ct(i)*filt
co(NO-i)=ct(NI-i)*filt
enddo
co=co/NO
call four2a(co,NO,1,1,1) !c2c FFT back to time domain
return
end subroutine downsample2
subroutine ft2_downsample(iwave,f0,c)
! Input: i*2 data in iwave() at sample rate 12000 Hz
! Output: Complex data in c(), sampled at 1200 Hz
include 'ft2_params.f90'
parameter (NFFT2=NMAX/16)
integer*2 iwave(NMAX)
complex c(0:NMAX/16-1)
complex c1(0:NFFT2-1)
complex cx(0:NMAX/2)
real x(NMAX)
equivalence (x,cx)
BW=4.0*75
df=12000.0/NMAX
x=iwave
call four2a(x,NMAX,1,-1,0) !r2c FFT to freq domain
ibw=nint(BW/df)
i0=nint(f0/df)
c1=0.
c1(0)=cx(i0)
do i=1,NFFT2/2
arg=(i-1)*df/bw
win=exp(-arg*arg)
c1(i)=cx(i0+i)*win
c1(NFFT2-i)=cx(i0-i)*win
enddo
c1=c1/NFFT2
call four2a(c1,NFFT2,1,1,1) !c2c FFT back to time domain
c=c1(0:NMAX/16-1)
return
end subroutine ft2_downsample