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More work on msk144 decoder.

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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6791 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke 2016-06-22 02:29:37 +00:00
parent 0bd4a2363a
commit 403f16d296
3 changed files with 68 additions and 37 deletions
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4
lib/analytic.f90
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@ -13,7 +13,7 @@ subroutine analytic(d,npts,nfft,c)
nh=nfft/2 nh=nfft/2
if(nfft.ne.nfft0) then if(nfft.ne.nfft0) then
t=1.0/2000.0 t=1.0/2000.0
beta=0.6 beta=0.1
pi=4.0*atan(1.0) pi=4.0*atan(1.0)
do i=1,nh+1 do i=1,nh+1
ff=(i-1)*df ff=(i-1)*df
@ -23,7 +23,7 @@ subroutine analytic(d,npts,nfft,c)
if(abs(f).gt.(1-beta)/(2*t) .and. abs(f).le.(1+beta)/(2*t)) then if(abs(f).gt.(1-beta)/(2*t) .and. abs(f).le.(1+beta)/(2*t)) then
h(i)=0.5*(1+cos((pi*t/beta )*(abs(f)-(1-beta)/(2*t)))) h(i)=0.5*(1+cos((pi*t/beta )*(abs(f)-(1-beta)/(2*t))))
endif endif
h(i)=sqrt(h(i)) ! h(i)=sqrt(h(i))
enddo enddo
nfft0=nfft nfft0=nfft
endif endif

100
lib/detectmsk144.f90
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@ -1,7 +1,7 @@
subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc) subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
use timer_module, only: timer use timer_module, only: timer
parameter (NSPM=864, NPTS=3*NSPM, MAXSTEPS=1500) parameter (NSPM=864, NPTS=3*NSPM, MAXSTEPS=1700, NFFT=NSPM)
character*22 msgreceived,allmessages(20) character*22 msgreceived,allmessages(20)
character*80 lines(100) character*80 lines(100)
character*512 pchk_file,gen_file character*512 pchk_file,gen_file
@ -9,7 +9,7 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
complex cdat(NPTS) !Analytic signal complex cdat(NPTS) !Analytic signal
complex cdat2(NPTS) complex cdat2(NPTS)
complex c(NSPM) complex c(NSPM)
complex ctmp(6000) complex ctmp(NFFT)
complex cb(42) !Complex waveform for sync word complex cb(42) !Complex waveform for sync word
complex cfac,cca,ccb complex cfac,cca,ccb
complex cc(NPTS) complex cc(NPTS)
@ -21,17 +21,18 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
integer*1 decoded(80) integer*1 decoded(80)
integer indices(MAXSTEPS) integer indices(MAXSTEPS)
integer ipeaks(10) integer ipeaks(10)
logical ismask(6000) logical ismask(NFFT)
real cbi(42),cbq(42) real cbi(42),cbq(42)
real detmet(-2:MAXSTEPS+3) real detmet(-2:MAXSTEPS+3)
real detfer(MAXSTEPS) real detfer(MAXSTEPS)
real tonespec(6000) real hannwindow(NPTS)
real rcw(12) real rcw(12)
real dd(NPTS) real dd(NPTS)
real ferrs(20) real ferrs(20)
real pp(12) !Half-sine pulse shape real pp(12) !Half-sine pulse shape
real snrs(20) real snrs(20)
real times(20) real times(20)
real tonespec(NFFT)
real*8 dt, df, fs, pi, twopi real*8 dt, df, fs, pi, twopi
real softbits(144) real softbits(144)
real*8 unscrambledsoftbits(128) real*8 unscrambledsoftbits(128)
@ -39,7 +40,7 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
logical first logical first
data first/.true./ data first/.true./
data s8/0,1,1,1,0,0,1,0/ data s8/0,1,1,1,0,0,1,0/
save df,first,cb,fs,nfft,pi,twopi,dt,s8,rcw,pp save df,first,cb,fs,pi,twopi,dt,s8,rcw,pp,hannwindow
if(first) then if(first) then
nmatchedfilter=1 nmatchedfilter=1
@ -51,8 +52,7 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
twopi=8d0*datan(1d0) twopi=8d0*datan(1d0)
fs=12000.0 fs=12000.0
dt=1.0/fs dt=1.0/fs
nfft=6000 !using a zero-padded fft to get 2 Hz bins df=fs/NFFT
df=fs/nfft
do i=1,12 do i=1,12
angle=(i-1)*pi/12.0 angle=(i-1)*pi/12.0
@ -60,6 +60,10 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
rcw(i)=(1-cos(angle))/2 rcw(i)=(1-cos(angle))/2
enddo enddo
do i=1,NPTS
hannwindow(i)=0.5*(1-cos(twopi*(i-1)/NPTS))
enddo
! define the sync word waveform ! define the sync word waveform
s8=2*s8-1 s8=2*s8-1
cbq(1:6)=pp(7:12)*s8(1) cbq(1:6)=pp(7:12)*s8(1)
@ -76,66 +80,87 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
endif endif
! fill the detmet, detferr arrays ! fill the detmet, detferr arrays
nstep=(n-NSPM)/256 nstep=(n-NPTS)/216 ! 72ms/4=18ms steps
detmet=0 detmet=0
detmax=-999.99
detfer=-999.99
do istp=1,nstep do istp=1,nstep
ns=1+256*(istp-1) ns=1+216*(istp-1)
ne=ns+NPTS-1 ne=ns+NSPM-1
if( ne .gt. n ) exit if( ne .gt. n ) exit
cdat=cbig(ns:ne) ctmp=cmplx(0.0,0.0)
ctmp(1:NSPM)=cbig(ns:ne)
! Coarse carrier frequency sync - seek tones at 2000 Hz and 4000 Hz in ! Coarse carrier frequency sync - seek tones at 2000 Hz and 4000 Hz in
! squared signal spectrum. ! squared signal spectrum.
! search range for coarse frequency error is +/- 100 Hz ! search range for coarse frequency error is +/- 100 Hz
ctmp=cmplx(0.0,0.0) ctmp=ctmp**2
ctmp(1:NPTS)=cdat**2
ctmp(1:12)=ctmp(1:12)*rcw ctmp(1:12)=ctmp(1:12)*rcw
ctmp(NPTS-11:NPTS)=ctmp(NPTS-11:NPTS)*rcw(12:1:-1) ctmp(NSPM-11:NSPM)=ctmp(NSPM-11:NSPM)*rcw(12:1:-1)
call four2a(ctmp,nfft,1,-1,1) ! ctmp(1:NSPM)=ctmp(1:NSPM)*hannwindow
call four2a(ctmp,NFFT,1,-1,1)
tonespec=abs(ctmp)**2 tonespec=abs(ctmp)**2
i3800=3800/df+1
i4200=4200/df+1
ismask=.false. ismask=.false.
ismask(1901:2101)=.true. ! high tone search window ismask(i3800:i4200)=.true. ! high tone search window
iloc=maxloc(tonespec,ismask) iloc=maxloc(tonespec,ismask)
ihpk=iloc(1) ihpk=iloc(1)
deltah=-real( (ctmp(ihpk-1)-ctmp(ihpk+1)) / (2*ctmp(ihpk)-ctmp(ihpk-1)-ctmp(ihpk+1)) )
ah=tonespec(ihpk) ah=tonespec(ihpk)
i1800=1800/df+1
i2200=2200/df+1
ismask=.false. ismask=.false.
ismask(901:1101)=.true. ! window for low tone ismask(i1800:i2200)=.true. ! window for low tone
iloc=maxloc(tonespec,ismask) iloc=maxloc(tonespec,ismask)
ilpk=iloc(1) ilpk=iloc(1)
deltal=-real( (ctmp(ilpk-1)-ctmp(ilpk+1)) / (2*ctmp(ilpk)-ctmp(ilpk-1)-ctmp(ilpk+1)) )
al=tonespec(ilpk) al=tonespec(ilpk)
fdiff=(ihpk-ilpk)*df fdiff=(ihpk+deltah-ilpk-deltal)*df
ferrh=(ihpk-2001)*df/2.0 i2000=2000/df+1
ferrl=(ilpk-1001)*df/2.0 i4000=4000/df+1
if( abs(fdiff-2000) .le. 16.0 ) then ferrh=(ihpk+deltah-i4000)*df/2.0
ferrl=(ilpk+deltal-i2000)*df/2.0
! if( abs(fdiff-2000) .le. 25.0 ) then
if( ah .ge. al ) then if( ah .ge. al ) then
ferr=ferrh ferr=ferrh
else else
ferr=ferrl ferr=ferrl
endif endif
else ! else
ferr=-999.99 ! ferr=-999.99
endif ! endif
detmet(istp)=ah+al ! detmet(istp)=ah+al
detmet(istp)=max(ah,al)
detfer(istp)=ferr detfer(istp)=ferr
! if( detmet(istp) .gt. detmax ) then
! open(unit=77,file="tonespec.dat")
! do i=1,NFFT
! write(77,*) (i-1)*df,tonespec(i)
! enddo
! close(77)
! detmax=detmet(istp)
! endif
!write(*,*) ihpk,ilpk,deltah,deltal,ferrh,ferrl,fdiff
enddo ! end of detection-metric and frequency error estimation loop enddo ! end of detection-metric and frequency error estimation loop
call indexx(detmet(1:nstep),nstep,indices) !find median of detection metric vector call indexx(detmet(1:nstep),nstep,indices) !find median of detection metric vector
xmed=detmet(indices(nstep/2)) xmed=detmet(indices(nstep/2))
detmet=detmet/xmed ! noise floor of detection metric is 1.0 detmet=detmet/xmed ! noise floor of detection metric is 1.0
ndet=0 ndet=0
do ip=1,20 ! use something like the "clean" algorithm to find candidates do ip=1,20 ! use something like the "clean" algorithm to find candidates
iloc=maxloc(detmet(1:nstep)) iloc=maxloc(detmet(1:nstep))
il=iloc(1) il=iloc(1)
if( (detmet(il) .lt. 1.5) .or. (abs(detfer(il)) .gt. 100.0) ) cycle if( (detmet(il) .lt. 2.0) .or. (abs(detfer(il)) .gt. 100.0) ) cycle
ndet=ndet+1 ndet=ndet+1
times(ndet)=((il-1)*256+NPTS/2)*dt times(ndet)=((il-1)*216+NSPM/2)*dt
ferrs(ndet)=detfer(il) ferrs(ndet)=detfer(il)
snrs(ndet)=10.0*log10(detmet(il))/2-5.0 !/2 because detmet is a 4th order moment snrs(ndet)=10.0*log10(detmet(il))/2-5.0 !/2 because detmet is a 4th order moment
detmet(il-3:il+3)=0.0 detmet(il-3:il+3)=0.0
! write(*,*) ndet,"snr ",snrs(ndet),"ferr ",ferrs(ndet)
enddo enddo
nmessages=0 nmessages=0
@ -182,14 +207,15 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
! fine adjustment of sync index ! fine adjustment of sync index
do i=1,6 do i=1,6
if( ic0+11+NSPM .le. NPTS ) then if( ic0+11+NSPM .le. NPTS ) then
bb(i) = sum( ( cdat(ic0+i-1+6:ic0+i-1+6+NSPM:6) * conjg( cdat(ic0+i-1:ic0+i-1+NSPM:6) ) )*2 ) bb(i) = sum( ( cdat(ic0+i-1+6:ic0+i-1+6+NSPM:6) * conjg( cdat(ic0+i-1:ic0+i-1+NSPM:6) ) )**2 )
else else
bb(i) = sum( ( cdat(ic0+i-1+6:NPTS:6) * conjg( cdat(ic0+i-1:NPTS-6:6) ) )*2 ) bb(i) = sum( ( cdat(ic0+i-1+6:NPTS:6) * conjg( cdat(ic0+i-1:NPTS-6:6) ) )**2 )
endif endif
enddo enddo
iloc=maxloc(abs(bb)) iloc=maxloc(abs(bb))
ibb=iloc(1) ibb=iloc(1)
bba=abs(bb(ibb)) bba=abs(bb(ibb))
bbp=atan2(-imag(bb(ibb)),-real(bb(ibb)))/(2*twopi*6*dt)
if( ibb .le. 3 ) ibb=ibb-1 if( ibb .le. 3 ) ibb=ibb-1
if( ibb .gt. 3 ) ibb=ibb-7 if( ibb .gt. 3 ) ibb=ibb-7
@ -260,7 +286,7 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
cfac=ccb*conjg(cca) cfac=ccb*conjg(cca)
ffin=atan2(imag(cfac),real(cfac))/(twopi*56*6*dt) ffin=atan2(imag(cfac),real(cfac))/(twopi*56*6*dt)
phase0=atan2(imag(cca+ccb),real(cca+ccb)) phase0=atan2(imag(cca+ccb),real(cca+ccb))
! Remove phase error - want constellation rotated so that sample points lie on I/Q axes ! Remove phase error - want constellation rotated so that sample points lie on I/Q axes
cfac=cmplx(cos(phase0),sin(phase0)) cfac=cmplx(cos(phase0),sin(phase0))
c=c*conjg(cfac) c=c*conjg(cfac)
@ -293,7 +319,7 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
nbadsync1=(8-sum( (2*hardbits(1:8)-1)*s8 ) )/2 nbadsync1=(8-sum( (2*hardbits(1:8)-1)*s8 ) )/2
nbadsync2=(8-sum( (2*hardbits(1+56:8+56)-1)*s8 ) )/2 nbadsync2=(8-sum( (2*hardbits(1+56:8+56)-1)*s8 ) )/2
nbadsync=nbadsync1+nbadsync2 nbadsync=nbadsync1+nbadsync2
if( nbadsync .gt. 6 ) cycle if( nbadsync .gt. 4 ) cycle
! normalize the softsymbols before submitting to decoder ! normalize the softsymbols before submitting to decoder
sav=sum(softbits)/144 sav=sum(softbits)/144
@ -331,7 +357,7 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
else else
msgreceived=' ' msgreceived=' '
ndither=-99 ! -99 is bad hash flag ndither=-99 ! -99 is bad hash flag
! write(78,1001) nutc,t0,nsnr,ipk,is,idf,iav,deltaf,fest,ffin,nbadsync1,nbadsync2, & ! write(78,1001) nutc,t0,nsnr,ipk,is,idf,iav,deltaf,fest,ferr,ferr2,ffin,bba,bbp,nbadsync1,nbadsync2, &
! phase0,niterations,ndither,msgreceived ! phase0,niterations,ndither,msgreceived
endif endif
endif endif
@ -343,9 +369,13 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc)
msgreceived=' ' msgreceived=' '
ndither=-98 ndither=-98
999 continue 999 continue
! write(78,1001) nutc,t0,nsnr,ipk,is,idf,iav,deltaf,fest,ffin,nbadsync1,nbadsync2, & if( nmessages .ge. 1 ) then
! write(78,1001) nutc,t0,nsnr,ipk,is,idf,iav,deltaf,fest,ferr,ferr2,ffin,bba,bbp,nbadsync1,nbadsync2, &
! phase0,niterations,ndither,msgreceived ! phase0,niterations,ndither,msgreceived
!1001 format(i6.6,f8.2,i4,i4,i4,i4,i4,f8.2,f8.2,f8.2,i4,i4,f8.2,i5,i5,2x,a22) ! call flush(78)
!1001 format(i6.6,f8.2,i4,i4,i4,i4,i4,f8.2,f8.2,f8.2,f8.2,f8.2,f8.2,f8.2,i4,i4,f8.2,i5,i5,2x,a22)
exit
endif
enddo enddo
return return
end subroutine detectmsk144 end subroutine detectmsk144

1
lib/msk144sim.f90
View File

@ -67,6 +67,7 @@ program msk144sim
call makepings(pings,NMAX,width,sig) call makepings(pings,NMAX,width,sig)
! call sgran()
do ifile=1,nfiles !Loop over requested number of files do ifile=1,nfiles !Loop over requested number of files
write(fname,1002) ifile !Output filename write(fname,1002) ifile !Output filename
1002 format('000000_',i6.6) 1002 format('000000_',i6.6)