mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-01 16:13:57 -04:00
025dd59fff
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@2967 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
180 lines
4.6 KiB
Fortran
180 lines
4.6 KiB
Fortran
subroutine sync24(dat,jz,DFTolerance,NFreeze,MouseDF,mode,mode4, &
|
|
dtx,dfx,snrx,snrsync,ccfblue,ccfred1,flip,width)
|
|
|
|
! Synchronizes JT4 data, finding the best-fit DT and DF.
|
|
|
|
parameter (NFFTMAX=2520) !Max length of FFTs
|
|
parameter (NHMAX=NFFTMAX/2) !Max length of power spectra
|
|
parameter (NSMAX=525) !Max number of half-symbol steps
|
|
integer DFTolerance !Range of DF search
|
|
real dat(jz)
|
|
real psavg(NHMAX) !Average spectrum of whole record
|
|
real s2(NHMAX,NSMAX) !2d spectrum, stepped by half-symbols
|
|
real ccfblue(-5:540) !CCF with pseudorandom sequence
|
|
real ccfred(-450:450) !Peak of ccfblue, as function of freq
|
|
real ccfred1(-224:224) !Peak of ccfblue, as function of freq
|
|
real tmp(1260)
|
|
save
|
|
|
|
! Do FFTs of twice symbol length, stepped by half symbols. Note that
|
|
! we have already downsampled the data by factor of 2.
|
|
|
|
nsym=207
|
|
nfft=2520
|
|
nh=nfft/2
|
|
nq=nfft/4
|
|
nsteps=jz/nq - 1
|
|
df=0.5*11025.0/nfft
|
|
psavg(1:nh)=0.
|
|
|
|
do j=1,nsteps !Compute spectrum for each step, get average
|
|
k=(j-1)*nq + 1
|
|
call ps24(dat(k),nfft,s2(1,j))
|
|
psavg(1:nh)=psavg(1:nh) + s2(1:nh,j)
|
|
enddo
|
|
|
|
call flat1(psavg,s2,nh,nsteps,NHMAX,NSMAX) !Flatten spectra
|
|
|
|
! Set freq and lag ranges
|
|
famin=200.
|
|
fbmax=2700.
|
|
fa=famin
|
|
fb=fbmax
|
|
if(NFreeze.eq.1) then
|
|
fa=max(famin,1270.46+MouseDF-DFTolerance)
|
|
fb=min(fbmax,1270.46+MouseDF+DFTolerance)
|
|
else
|
|
fa=max(famin,1270.46+MouseDF-600)
|
|
fb=min(fbmax,1270.46+MouseDF+600)
|
|
endif
|
|
ia=fa/df
|
|
ib=fb/df
|
|
if(mode.eq.7) then
|
|
ia=ia - 3*mode4
|
|
ib=ib - 3*mode4
|
|
endif
|
|
i0=nint(1270.46/df)
|
|
lag1=-5
|
|
lag2=59
|
|
syncbest=-1.e30
|
|
syncbest2=-1.e30
|
|
ccfred=0.
|
|
|
|
do i=ia,ib !Find best frequency channel for CCF
|
|
|
|
call xcor24(s2,i,nsteps,nsym,lag1,lag2,mode4,ccfblue,ccf0,lagpk0,flip)
|
|
j=i-i0
|
|
if(mode.eq.7) j=j + 3*mode4
|
|
if(j.ge.-372 .and. j.le.372) ccfred(j)=ccf0
|
|
|
|
! Find rms of the CCF, without main peak
|
|
call slope(ccfblue(lag1),lag2-lag1+1,lagpk0-lag1+1.0)
|
|
sync=abs(ccfblue(lagpk0))
|
|
ppmax=psavg(i)-1.0
|
|
|
|
! Find best sync value
|
|
if(sync.gt.syncbest2) then
|
|
ipk2=i
|
|
lagpk2=lagpk0
|
|
syncbest2=sync
|
|
endif
|
|
|
|
! We are most interested if snrx will be more than -30 dB.
|
|
if(ppmax.gt.0.2938) then !Corresponds to snrx.gt.-30.0
|
|
if(sync.gt.syncbest) then
|
|
ipk=i
|
|
lagpk=lagpk0
|
|
syncbest=sync
|
|
endif
|
|
endif
|
|
enddo
|
|
|
|
! If we found nothing with snrx > -30 dB, take the best sync that *was* found.
|
|
if(syncbest.lt.-10.) then
|
|
ipk=ipk2
|
|
lagpk=lagpk2
|
|
syncbest=syncbest2
|
|
endif
|
|
|
|
dfx=(ipk-i0)*df
|
|
if(mode.eq.7) dfx=dfx + 3*mode4*df
|
|
|
|
! Peak up in time, at best whole-channel frequency
|
|
call xcor24(s2,ipk,nsteps,nsym,lag1,lag2,mode4,ccfblue,ccfmax,lagpk,flip)
|
|
xlag=lagpk
|
|
if(lagpk.gt.lag1 .and. lagpk.lt.lag2) then
|
|
call peakup(ccfblue(lagpk-1),ccfmax,ccfblue(lagpk+1),dx2)
|
|
xlag=lagpk+dx2
|
|
endif
|
|
|
|
! Find rms of the CCF, without the main peak
|
|
call slope(ccfblue(lag1),lag2-lag1+1,xlag-lag1+1.0)
|
|
sq=0.
|
|
nsq=0
|
|
do lag=lag1,lag2
|
|
if(abs(lag-xlag).gt.2.0) then
|
|
sq=sq+ccfblue(lag)**2
|
|
nsq=nsq+1
|
|
endif
|
|
enddo
|
|
rms=sqrt(sq/nsq)
|
|
snrsync=abs(ccfblue(lagpk))/rms - 1.1 !Empirical
|
|
|
|
dt=2.0/11025.0
|
|
istart=xlag*nq
|
|
dtx=istart*dt
|
|
snrx=-99.0
|
|
ppmax=psavg(ipk)-1.0
|
|
|
|
if(ppmax.gt.0.0001) then
|
|
snrx=db(ppmax*df/2500.0) + 7.5 !Empirical
|
|
if(mode.eq.7) snrx=snrx + 3.0 !Empirical
|
|
endif
|
|
if(snrx.lt.-33.0) snrx=-33.0
|
|
|
|
! Compute width of sync tone to outermost -3 dB points
|
|
i1=max(-450,ia-i0)
|
|
i2=min(450,ib-i0)
|
|
call pctile(ccfred(i1),i2-i1+1,45,base)
|
|
|
|
jpk=ipk-i0
|
|
if(abs(jpk).gt.450) then
|
|
print*,'sync24 a:',jpk,ipk,i0
|
|
snrsync=0.
|
|
go to 999
|
|
else
|
|
stest=base + 0.5*(ccfred(jpk)-base) ! -3 dB
|
|
endif
|
|
do i=-10,0
|
|
if(jpk+i.ge.-371) then
|
|
if(ccfred(jpk+i).gt.stest) go to 30
|
|
endif
|
|
enddo
|
|
i=0
|
|
30 continue
|
|
if(abs(jpk+i-1).gt.450 .or. abs(jpk+i).gt.450) then
|
|
print*,'sync24 b:',jpk,i
|
|
else
|
|
x1=i-0.5
|
|
endif
|
|
|
|
do i=10,0,-1
|
|
if(jpk+i.le.371) then
|
|
if(ccfred(jpk+i).gt.stest) go to 32
|
|
endif
|
|
enddo
|
|
i=0
|
|
32 x2=i+0.5
|
|
width=x2-x1
|
|
if(width.gt.1.2) width=sqrt(width**2 - 1.44)
|
|
width=df*width
|
|
width=max(0.0,min(99.0,width))
|
|
|
|
do i=-224,224
|
|
ccfred1(i)=ccfred(i)
|
|
enddo
|
|
|
|
999 return
|
|
end subroutine sync24
|
|
|