Compute analog of "orange sync curve" in MAP65; use it to determind ipol for a decode candidate.

map65/libm65/CMakeLists.txt

@@ -1,4 +1,8 @@
 set (libm65_FSRCS
+# Modules come first:
+  wideband_sync.f90
+
+# Non-module Fortran routines:
   afc65b.f90
   astro.f90
   astro0.f90

map65/libm65/decode0.f90

@@ -1,8 +1,8 @@
 subroutine decode0(dd,ss,savg,nstandalone)
 
+  use wideband_sync
   use timer_module, only: timer
   parameter (NSMAX=60*96000)
-  parameter (NFFT=32768)
 
   real*4 dd(4,NSMAX),ss(4,322,NFFT),savg(4,NFFT)
   real*8 fcenter
@@ -17,9 +17,12 @@ subroutine decode0(dd,ss,savg,nstandalone)
   data neme0/-99/,mcall3b/1/
   save
 
-!  write(60) ss,savg
   call timer('decode0 ',0)
 
+  call timer('wb_sync ',0)
+  call wb_sync(ss,savg)
+  call timer('wb_sync ',1)
+
   if(newdat.ne.0) then
      nz=52*96000
      hist=0

map65/libm65/m65.f90

@@ -107,7 +107,6 @@ program m65
      nch=2
      if(nxpol.eq.1) nch=4
 
-!     if(ifile.eq.ifile1) call timer('m65     ',0)
      do irec=1,9999999
         read(10,end=10) i2
         do i=1,NREAD,nch
@@ -139,9 +138,8 @@ program m65
                 rejecty,pxdb,pydb,ssz5a,nkhz,ihsym,nzap,slimit,lstrong)
            call timer('symspec ',1)
            nhsym0=nhsym
-!           if(ihsym.ge.278) go to 10
         endif
-     enddo
+     enddo  ! irec
 
 10   continue
      if(iqadjust.ne.0) write(*,3002) rejectx,rejecty
@@ -149,7 +147,7 @@ program m65
      nutc=nutc0
      nstandalone=1
      call decode0(dd,ss,savg,nstandalone)
-  enddo
+  enddo  ! ifile
 
   call timer('m65     ',1)
   call timer('m65     ',101)

map65/libm65/map65a.f90

@@ -5,10 +5,11 @@ subroutine map65a(dd,ss,savg,newdat,nutc,fcenter,ntol,idphi,nfa,nfb,        &
 
 !  Processes timf2 data from Linrad to find and decode JT65 signals.
 
+  use wideband_sync
   use timer_module, only: timer
+
   parameter (MAXMSG=1000)            !Size of decoded message list
   parameter (NSMAX=60*96000)
-  parameter (NFFT=32768)
   real dd(4,NSMAX)
   real*4 ss(4,322,NFFT),savg(4,NFFT)
   real tavg(-50:50)                  !Temp for finding local base level

map65/libm65/q65b.f90

@@ -2,7 +2,9 @@ subroutine q65b(nutc,fcenter,nfcal,nfsample,ikhz,mousedf,ntol,xpol,  &
      mycall0,hiscall0,hisgrid,mode_q65)
 
   use q65_decode
+  use wideband_sync
   use timer_module, only: timer
+
   parameter (MAXFFT1=5376000)              !56*96000
   parameter (MAXFFT2=336000)               !56*6000 (downsampled by 1/16)
   parameter (NMAX=60*12000)
@@ -10,6 +12,7 @@ subroutine q65b(nutc,fcenter,nfcal,nfsample,ikhz,mousedf,ntol,xpol,  &
   complex ca(MAXFFT1),cb(MAXFFT1)          !FFTs of raw x,y data
   complex cx(0:MAXFFT2-1),cy(0:MAXFFT2-1),cz(0:MAXFFT2)
   logical xpol
+  integer ipk1(1)
   real*8 fcenter
   character*12 mycall0,hiscall0
   character*12 mycall,hiscall
@@ -67,43 +70,50 @@ subroutine q65b(nutc,fcenter,nfcal,nfsample,ikhz,mousedf,ntol,xpol,  &
 !   96000  5376000  0.017857143  336000   6000.000
 !   95238  5120000  0.018601172  322560   5999.994
 
+! Get best ipol by referring to the "orange sync curve".
+  ff=ikhz+0.001*(mousedf+1270.459)              !supposed freq of sync tone
+  ifreq=nint(1000.0*(ff-77.0)*32768.0/96000.0)  !Freq index into ss(4,322,32768)
+  dff=96000.0/32768.0
+  ia=nint(ifreq-ntol/dff)
+  ib=nint(ifreq+ntol/dff)
+  ipk1=maxloc(sync_dat(ia:ib,2))
+  ipk=ia+ipk1(1)-1
+  ipol=nint(sync_dat(ipk,4))
+
   nsnr1=-99
-  npol=1
+  if(ipol.eq.1) cz(0:MAXFFT2-1)=cx
-  if(xpol) npol=4
+  if(ipol.eq.2) cz(0:MAXFFT2-1)=0.707*(cx+cy)
-  do ipol=1,npol
+  if(ipol.eq.3) cz(0:MAXFFT2-1)=cy
-     if(ipol.eq.1) cz(0:MAXFFT2-1)=cx
+  if(ipol.eq.4) cz(0:MAXFFT2-1)=0.707*(cx-cy)
-     if(ipol.eq.2) cz(0:MAXFFT2-1)=0.707*(cx+cy)
+  cz(MAXFFT2)=0.
-     if(ipol.eq.3) cz(0:MAXFFT2-1)=cy
-     if(ipol.eq.4) cz(0:MAXFFT2-1)=0.707*(cx-cy)
-     cz(MAXFFT2)=0.
 !Transform to time domain (real), fsample=12000 Hz
-     call four2a(cz,2*nfft2,1,1,-1)
+  call four2a(cz,2*nfft2,1,1,-1)
-     do i=0,nfft2-1
+  do i=0,nfft2-1
-        j=nfft2-1-i
+     j=nfft2-1-i
-        iwave(2*i+1)=nint(real(cz(j)))
+     iwave(2*i+1)=nint(real(cz(j)))
-        iwave(2*i+2)=nint(aimag(cz(j)))
+     iwave(2*i+2)=nint(aimag(cz(j)))
-     enddo
+  enddo
-     iwave(2*nfft2+1:)=0
+  iwave(2*nfft2+1:)=0
-     nsubmode=mode_q65-1
+  nsubmode=mode_q65-1
-     nfa=300
+  nfa=300
-     nfb=2883
+  nfb=2883
-     nfqso=1000 + mousedf
+  nfqso=1000 + mousedf
-     newdat=1
+  newdat=1
-     nagain=0
+  nagain=0
-     nsnr0=-99             !Default snr for no decode
+  nsnr0=-99             !Default snr for no decode
-     call timer('mmdec   ',0)
+
-     call map65_mmdec(nutc,iwave,nsubmode,nfa,nfb,nfqso,ntol,newdat,nagain,  &
+  call timer('mmdec   ',0)
-          mycall,hiscall,hisgrid)
+  call map65_mmdec(nutc,iwave,nsubmode,nfa,nfb,nfqso,ntol,newdat,nagain,  &
-     call timer('mmdec   ',1)
+       mycall,hiscall,hisgrid)
-     if(nsnr0.gt.nsnr1) then
+  call timer('mmdec   ',1)
-        nsnr1=nsnr0
+  if(nsnr0.gt.nsnr1) then
-        xdt1=xdt0
+     nsnr1=nsnr0
-        nfreq1=nfreq0
+     xdt1=xdt0
-        msg1=msg0
+     nfreq1=nfreq0
-        cq1=cq0
+     msg1=msg0
-        ipol1=45*ipol
+     cq1=cq0
-     endif
+     ipol1=45*(ipol-1)
-  enddo  !ipol
+  endif
 
   nfreq=nfreq1+mousedf-1000
   write(line,1020) ikhz,nfreq,ipol1,nutc,xdt1,nsnr1,msg1(1:27),cq1

map65/libm65/wideband_sync.f90

@@ -0,0 +1,70 @@
+module wideband_sync
+
+  parameter (NFFT=32768)
+  integer isync(22)
+  real sync_dat(NFFT,4)     !fkhz, ccfmax, xdt, ipol
+
+  contains
+  
+subroutine wb_sync(ss,savg)
+
+! Compute "orange sync curve" using the Q65 sync pattern
+
+  parameter (LAGMAX=30)
+  real ss(4,322,NFFT)
+  real savg(4,NFFT)
+  logical first
+  integer isync0(22)
+! Q65 sync symbols
+  data isync0/1,9,12,13,15,22,23,26,27,33,35,38,46,50,55,60,62,66,69,74,76,85/
+  data first/.true./
+  save first
+
+  tstep=2048.0/11025.0
+  if(first) then
+     fac=0.6/tstep
+     do i=1,22                                !Expand the sync stride
+        isync(i)=nint((isync0(i)-1)*fac) + 1
+     enddo
+     first=.false.
+  endif
+
+  df=96000.0/NFFT
+  ia=nint(7000.0/df)          !Flat frequency range for WSE converters
+  ib=nint(89000.0/df)
+  lagbest=-1
+  ipolbest=-1
+
+  do i=ia,ib
+     ccfmax=0.
+     do ipol=1,4
+        do lag=0,LAGMAX
+           ccf=0.
+           do j=1,22
+              k=isync(j) + lag
+              ccf=ccf + ss(ipol,k,i) 
+           enddo
+           ccf=ccf - savg(ipol,i)*22.0/322.0
+           if(ccf.gt.ccfmax) then
+              ipolbest=ipol
+              lagbest=lag
+              ccfmax=ccf
+           endif
+        enddo  ! lag
+     enddo  !ipol
+
+     fkhz=0.001*i*df + 125.0 - 48.0
+     xdt=lagbest*tstep-1.0
+     sync_dat(i,1)=fkhz
+     sync_dat(i,2)=ccfmax
+     sync_dat(i,3)=xdt
+     sync_dat(i,4)=ipolbest
+!     write(14,3010) i,sync_dat(i,1:3),nint(sync_dat(i,4))
+!3010 format(i6,3f10.3,i5)
+
+  enddo
+
+  return
+end subroutine wb_sync
+
+end module wideband_sync