Code cleanup.

lib/decoder.f90

@@ -197,9 +197,8 @@ subroutine multimode_decoder(ss,id2,params,nfsample)
   if(params%nmode.eq.66) then
 ! We're in QRA66 mode
      call timer('decqra66',0)
-     call my_qra66%decode(qra66_decoded,id2,params%nutc,params%nfa,         &
+     call my_qra66%decode(qra66_decoded,id2,params%nutc,params%nfqso,        &
-          params%nfb,params%nfqso,params%ndepth,logical(params%lapcqonly),  &
+          params%ntol,params%ndepth,mycall,hiscall,hisgrid)
-          mycall,hiscall,hisgrid)
      call timer('decqra66',1)
      go to 800
   endif

lib/qra66_decode.f90

@@ -28,7 +28,7 @@ module qra66_decode
 
 contains
 
-  subroutine decode(this,callback,iwave,nutc,nfa,nfb,nfqso,ndepth,lapdx,   &
+  subroutine decode(this,callback,iwave,nutc,nfqso,ntol,ndepth,   &
        mycall,hiscall,hisgrid)
 
     use timer_module, only: timer
@@ -41,12 +41,9 @@ contains
     character(len=6) :: hisgrid
     character*37 decoded
     integer*2 iwave(NFFT1)                 !Raw data
-    integer ipk(1)
     integer dat4(12)
     logical lapdx,ltext
-    complex c00(0:NFFT1-1)                 !Spectrum, then analytic signal
+    complex c0(0:NFFT1-1)                  !Analytic signal, 6000 S/s
-    complex c0(0:NFFT1-1)                  !Snalytic signal
-    real s(900)
     real s3(-64:127,63)
     real a(5)
     data nc1z/-1/,nc2z/-1/,ng2z/-1/,maxaptypez/-1/
@@ -67,12 +64,11 @@ contains
     b90=20.0                 !8 to 25 is OK; not very critical
     nFadingModel=1
 
-! These probably need work:
+! AP control could be done differently, but this works well:
     maxaptype=0
     if(ndepth.eq.2) maxaptype=3
     if(ndepth.eq.3) maxaptype=5
 
-! Prime the decoder for possible AP decoding
     if(nc1.ne.nc1z .or. nc2.ne.nc2z .or. ng2.ne.ng2z .or.            &
          maxaptype.ne.maxaptypez) then
        do naptype=0,maxaptype
@@ -87,60 +83,39 @@ contains
     endif
     naptype=maxaptype
 
-! Compute the full-length spectrum
+! Downsample to give complex data at 6000 S/s
     fac=2.0/NFFT1
     c0=fac*iwave
     call four2a(c0,NFFT1,1,-1,1)           !Forward c2c FFT
-
-    nadd=101
-    nh=nadd/2
-    df2=nh*df1
-    iz=3000.0/df2
-    do i=1,iz                              !Compute smoothed spectrum
-       s(i)=0.
-       j0=nh*i
-       do j=j0-nh,j0+nh
-          s(i)=s(i) + real(c0(j))**2 + aimag(c0(j))**2
-       enddo
-    enddo
-    call smo121(s,iz)
-    ia=1450/df2
-    ib=1550/df2
-    s(:ia)=0.
-    s(ib:)=0.
-    ipk=maxloc(s)
-    f0=df2*ipk(1) - 0.5*baud               !Candidate sync frequency
-
     c0(NFFT2/2+1:NFFT2)=0.                 !Zero the top half
     c0(0)=0.5*c0(0)
     call four2a(c0,nfft2,1,1,1)            !Inverse c2c FFT
 
     ntol=100
     call sync66a(iwave,15*12000,nsps,nfqso,ntol,xdt,f0,snr1)
-    jpk=(xdt+0.5)*6000 - 384       !### Empirical ###
+    jpk=(xdt+0.5)*6000 - 384               !### Empirical ###
     if(jpk.lt.0) jpk=0
-    c00=c0
     a=0.
-    a(1)=-(f0 + 2.0*baud)           !For sync66a
+    a(1)=-(f0 + 2.0*baud)                  !Data tones start 2 bins higher
-    call twkfreq(c00,c0,15*6000,6000.0,a)
+    call twkfreq(c0,c0,15*6000,6000.0,a)
     xdt=jpk/6000.0 - 0.5
     call spec66(c0(jpk:jpk+85*NSPS/2-1),s3)
 
-    do j=1,63
+    do j=1,63                              !Normalize to symbol baseline
        call pctile(s3(:,j),192,40,base)
        s3(:,j)=s3(:,j)/base
     enddo
 
-! Apply AGC
     s3max=20.0
-    do j=1,63
+    do j=1,63                              !Apply AGC to suppress pings
      xx=maxval(s3(-64:127,j))
      if(xx.gt.s3max) s3(-64:127,j)=s3(-64:127,j)*s3max/xx
     enddo
-  
+
+!Call Nico's QRA64 decoder
     call qra64_dec(s3,nc1,nc2,ng2,naptype,0,nSubmode,b90,      &
          nFadingModel,dat4,snr2,irc)
-    snr2=snr2 + 6.0
+    snr2=snr2 + 5.563                      !10*log(6912/1920)
     if(irc.gt.0) call badmsg(irc,dat4,nc1,nc2,ng2)
 
     decoded='                                     '