FT8 now uses nsps=1920.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7784 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/fsk4hf/ft8_downsample.f90

@@ -1,9 +1,10 @@
 subroutine ft8_downsample(dd,newdat,f0,c1)
 
-! Downconvert to complex data sampled at 187.5 Hz, 32 samples/symbol
+! Downconvert to complex data sampled at 200 Hz ==> 32 samples/symbol
 
   parameter (NMAX=15*12000)
-  parameter (NFFT1=200000,NFFT2=3125)      !200000/64 = 3125
+  parameter (NFFT1=192000,NFFT2=3200)      !192000/60 = 3200
+  
   logical newdat
   complex c1(0:NFFT2-1)
   complex cx(0:NFFT1/2)
@@ -20,7 +21,7 @@ subroutine ft8_downsample(dd,newdat,f0,c1)
   endif
 
   df=12000.0/NFFT1
-  baud=12000.0/2048.0
+  baud=12000.0/1920.0
   i0=nint(f0/df)
   ft=f0+8.0*baud
   it=min(nint(ft/df),NFFT1/2)

lib/fsk4hf/ft8_params.f90

@@ -3,8 +3,8 @@ parameter (KK=87)                     !Information bits (75 + CRC12)
 parameter (ND=58)                     !Data symbols
 parameter (NS=21)                     !Sync symbols (3 @ Costas 7x7)
 parameter (NN=NS+ND)                  !Total channel symbols (79)
-parameter (NSPS=2048)                 !Samples per symbol at 12000 S/s
-parameter (NZ=NSPS*NN)                !Samples in full 15 s waveform (161,792)
+parameter (NSPS=1920)                 !Samples per symbol at 12000 S/s
+parameter (NZ=NSPS*NN)                !Samples in full 15 s waveform (151,680)
 parameter (NMAX=15*12000)             !Samples in iwave (180,000)
 parameter (NFFT1=2*NSPS, NH1=NFFT1/2) !Length of FFTs for symbol spectra
 parameter (NHSYM=2*NMAX/NH1-1)        !Number of symbol spectra (1/2-symbol steps)

lib/fsk4hf/ft8b.f90

@@ -12,14 +12,14 @@ subroutine ft8b(dd0,newdat,nfqso,f1,xdt,nharderrors,dmin,nbadcrc,message,xsnr)
   real dd0(15*12000)
   integer*1 decoded(KK),apmask(3*ND),cw(3*ND)
   integer itone(NN)
-  complex cd0(3125)
+  complex cd0(3200)
   complex ctwk(32)
   complex csymb(32)
   logical newdat
 
   max_iterations=40
   norder=2
-  fs2=12000.0/64.0
+  fs2=12000.0/60.0
   dt2=1.0/fs2
   twopi=8.0*atan(1.0)
   delfbest=0.

lib/fsk4hf/ft8sim.f90

@@ -52,12 +52,11 @@ program ft8sim
 !  call sgran()
   c=0.
   do ifile=1,nfiles
-
      c0=0.
      do isig=1,25
         f0=(isig+2)*100.0
         phi=0.0
-        k=-1 + nint(xdt/dt)
+        k=-1 + nint(xdt+0.5/dt)
         do j=1,NN                             !Generate complex waveform
            dphi=twopi*(f0+itone(j)*baud)*dt
            if(k.eq.0) phi=-dphi

lib/fsk4hf/sync8.f90

@@ -1,7 +1,7 @@
 subroutine sync8(iwave,nfa,nfb,nfqso,s,candidate,ncand)
 
   include 'ft8_params.f90'
-  parameter (JZ=35)                            !DT up to +/- 3 s
+  parameter (JZ=31)                            !DT up to +/- 2.5 s
   complex cx(0:NH1)
   real s(NH1,NHSYM)
   real savg(NH1)
@@ -20,9 +20,9 @@ subroutine sync8(iwave,nfa,nfb,nfqso,s,candidate,ncand)
 
 ! Compute symbol spectra at half-symbol steps.  
   savg=0.
-  istep=NSPS/2                                !1024
-  tstep=istep/12000.0                         !0.085333 s
-  df=12000.0/NFFT1                            !2.93 Hz
+  istep=NSPS/2                                !960
+  tstep=istep/12000.0                         !0.08 s
+  df=12000.0/NFFT1                            !3.125 Hz
 
 ! Compute symbol spectra at half-symbol steps
   fac=1.0/300.0
@@ -38,6 +38,10 @@ subroutine sync8(iwave,nfa,nfb,nfqso,s,candidate,ncand)
      savg=savg + s(1:NH1,j)                   !Average spectrum
   enddo
   savg=savg/NHSYM
+!  do i=1,NH1
+!     write(51,3051) i*df,savg(i),db(savg(i))
+!3051 format(f10.3,e12.3,f12.3)
+!  enddo
 
   ia=max(1,nint(nfa/df))
   ib=nint(nfb/df)

lib/fsk4hf/sync8d.f90

@@ -19,10 +19,10 @@ subroutine sync8d(cd0,i0,ctwk,itwk,sync)
 ! Set some constants and compute the csync array.  
   if( first ) then
     twopi=8.0*atan(1.0)
-    fs2=12000.0/64.0                        !Sample rate after downsampling
+    fs2=12000.0/60.0                        !Sample rate after downsampling
     dt2=1/fs2                               !Corresponding sample interval
     taus=32*dt2                             !Symbol duration
-    baud=1/taus                             !Keying rate
+    baud=1.0/taus                             !Keying rate
     do i=0,6
       phi=0.0
       dphi=twopi*icos7(i)*baud*dt2  

lib/ft8_decode.f90

@@ -64,7 +64,7 @@ contains
             f1,nbadcrc,message)
 !       write(*,'(f7.2,i5,f7.2,f9.1,i5,f7.2,2x,a22)') sync,nsnr,xdt,f1,nharderrors,dmin,message
 !       write(13,1110) datetime,0,nsnr,xdt,f1,nharderrors,dmin,message
-1110   format(a13,2i4,f6.2,f7.1,i4,' ~ ',f6.2,2x,a22,'  FT8')
+!1110   format(a13,2i4,f6.2,f7.1,i4,' ~ ',f6.2,2x,a22,'  FT8')
 !       write(51,3051) xdt,f1,sync,dmin,nsnr,nharderrors,nbadcrc,message
 !3051   format(4f9.1,3i5,2x,a22)
 !       flush(51)