Fixed signal subtraction for E speed signals

lib/js8/js8dec.f90

@@ -95,8 +95,10 @@ subroutine js8dec(dd0,newdat,nQSOProgress,nfqso,nftx,ndepth,lapon,lapcqonly,   &
   delfbest=0.
   ibest=0
 
+  if(NWRITELOG.eq.1) then
     write(*,*) '<DecodeDebug> downsampling', fs2, dt2
     flush(6)
+  endif
 
   call timer('js8_down',0)
   call js8_downsample(dd0,newdat,f1,cd0)   !Mix f1 to baseband and downsample

lib/js8/subtractjs8.f90

@@ -1,5 +1,4 @@
 subroutine subtractjs8(dd,itone,f0,dt)
-
 ! Subtract an ft8 signal
 !
 ! Measured signal  : dd(t)    = a(t)cos(2*pi*f0*t+theta(t))
@@ -7,14 +6,10 @@ subroutine subtractjs8(dd,itone,f0,dt)
 ! Complex amp      : cfilt(t) = LPF[ dd(t)*CONJG(cref(t)) ]
 ! Subtract         : dd(t)    = dd(t) - 2*REAL{cref*cfilt}
 
-  use timer_module, only: timer
-
-  !include 'js8_params.f90'
-  
   parameter (NFRAME=NSPS*NN)
   parameter (NFFT=NMAX, NFILT=1400)
 
-  real*4  dd(NMAX), window(-NFILT/2:NFILT/2)
+  real dd(NMAX), window(-NFILT/2:NFILT/2)
   complex cref,camp,cfilt,cw
   integer itone(NN)
   logical first
@@ -30,51 +25,72 @@ subroutine subtractjs8(dd,itone,f0,dt)
   endif
 
   call genjs8refsig(itone,cref,f0)
+
   camp=0.
-  do i=1,nframe
+  do i=1,NFRAME
     id=nstart-1+i 
     if(id.ge.1.and.id.le.NMAX) camp(i)=dd(id)*conjg(cref(i))
   enddo
 
   if(NWRITELOG.eq.1) then
-      write(*,*) '<DecodeDebug> filtering', nfft
+      write(*,*) '<DecodeDebug> filtering', NFFT
       flush(6)
   endif
 
   if(first) then
 ! Create and normalize the filter
+      if(NWRITELOG.eq.1) then
+          write(*,*) '<DecodeDebug> creating and normalizing filter'
+          flush(6)
+      endif
+
       pi=4.0*atan(1.0)
-     fac=1.0/float(nfft)
+      fac=1.0/float(NFFT)
       sum=0.0
       do j=-NFILT/2,NFILT/2
          window(j)=cos(pi*j/NFILT)**2
          sum=sum+window(j)
       enddo
+
       cw=0.
-     cw(1:NFILT+1)=window/sum
+      ! this ultimately shifts 1/2 of the window out of computation
-     cw=cshift(cw,NFILT/2+1)
+      ! since it's multiplied against cfilt whiich will only have amp
-     call four2a(cw,nfft,1,-1,1)
+      ! values for NFRAME length, which will always be > 20000 samples
+      ! longer than the NFRAME.
+      ! cw(1:NFILT+1)=window/sum
+      ! cw=cshift(cw,NFILT/2+1)
+      cw(1:NFILT/2)=window(1:NFILT/2)
+      ! we really don't even need the second half of the window.
+      ! start=NMAX-NFILT/2
+      ! end=NMAX-NFILT+1
+      ! cw(start:end)=window(-NFILT/2:1)
+      cw=cw/sum
+      call four2a(cw,NFFT,1,-1,1)
       cw=cw*fac
       first=.false.
   endif
 
+  if(NWRITELOG.eq.1) then
+      write(*,*) '<DecodeDebug> generating complex amplitude'
+      flush(6)
+  endif
+
   cfilt=0.0
-  cfilt(1:nframe)=camp(1:nframe)
+  cfilt(1:NFRAME)=camp(1:NFRAME)
-  call four2a(cfilt,nfft,1,-1,1)
+  call four2a(cfilt,NFFT,1,-1,1)
-  cfilt(1:nfft)=cfilt(1:nfft)*cw(1:nfft)
+  cfilt(1:NFFT)=cfilt(1:NFFT)*cw(1:NFFT)
-  call four2a(cfilt,nfft,1,1,1)
+  call four2a(cfilt,NFFT,1,1,1)
 
   if(NWRITELOG.eq.1) then
-      write(*,*) '<DecodeDebug> subtracting filtered reference', nfft
+      write(*,*) '<DecodeDebug> subtracting filtered reference', NFFT
       flush(6)
   endif
 
 ! Subtract the reconstructed signal
-  do i=1,nframe
+  do i=1,NFRAME
      j=nstart+i-1
      if(j.ge.1 .and. j.le.NMAX) dd(j)=dd(j)-2*REAL(cfilt(i)*cref(i))
   enddo
 
   return
 end subroutine subtractjs8
-

lib/js8e_decode.f90

@@ -109,10 +109,6 @@ contains
         endif
 
         call timer('js8dec  ',0)
-        ! for now, subtraction of slow is not possible
-        if(NSPS.gt.1920) then
-            lsubtract=.false.
-        endif
         call js8dec(dd,newdat,nQSOProgress,nfqso,nftx,ndepth,lft8apon,       &
              lapcqonly,napwid,lsubtract,nagain,iaptype,mycall12,mygrid6,   &
              hiscall12,bcontest,sync,f1,xdt,xbase,apsym,nharderrors,dmin,  &