Work in progress toward trying a Q65-style sync.

lib/superfox/sfox_gen.f90

@@ -4,43 +4,31 @@ subroutine sfox_gen(idat,f0,fsample,isync,cdat)
   complex cdat(NMAX)                     !Generated complex waveform
   complex w,wstep
   integer idat(NN)
-  integer isync(50)
+  integer isync(44)
+  integer itone(171)
 
   twopi=8.0*atan(1.0)
-  tsync=NS*NSPS/fsample
+
+! Create the itone sequence: data symbols and interspersed sync symbols
+  j=1
+  k=0
+  do i=1,NDS
+     if(j.le.NS .and. i.eq.isync(min(j,NS))) then
+        j=j+1                   !Index for next sync symbol
+        itone(i)=0              !Insert sync symbol at tone 0
+     else
+        k=k+1
+        itone(i)=idat(k) + 1    !Symbol value 0 is transmitted at tone 1, etc.
+     endif
+  enddo
+  
   df=fsample/NSPS
   w=1.0
   j=0
-  k=0
   i0=NQ/2
-! First group of data symbols:
+! Generate the waveform
-  do n=1,ND1
+  do k=1,NDS
-     k=k+1
+     dphi=(f0 + (itone(k)-i0)*df)*(twopi/fsample)
-     dphi=(f0 + (idat(k)-i0)*df)*(twopi/fsample)
-     wstep=cmplx(cos(dphi),sin(dphi))
-     do i=1,NSPS
-        j=j+1
-        w=w*wstep
-        cdat(j)=w
-     enddo
-  enddo
-
-! Insert sync symbols
-  do n=1,NS
-     dphi=(f0 + (isync(n)-i0)*df)*(twopi/fsample)
-     wstep=cmplx(cos(dphi),sin(dphi))
-     do i=1,NSPS
-        j=j+1
-        w=w*wstep
-        cdat(j)=w
-     enddo
-  enddo
-
-  
-! Final group of data symbols:
-  do n=1,ND2
-     k=k+1
-     dphi=(f0 + (idat(k)-i0)*df)*(twopi/fsample)
      wstep=cmplx(cos(dphi),sin(dphi))
      do i=1,NSPS
         j=j+1

lib/superfox/sfox_mod.f90

@@ -1,10 +1,10 @@
 module sfox_mod
   
   parameter (NMAX=15*12000)       !Samples in iwave (180,000)
-  integer MM,NQ,NN,KK,ND1,ND2,NFZ,NSPS,NS,NSYNC,NZ,NFFT,NFFT1
+  integer MM,NQ,NN,KK,NS,NDS,NFZ,NSPS,NSYNC,NZ,NFFT,NFFT1
 
 contains
-  subroutine sfox_init(mm0,nn0,kk0,itu,fspread,delay,fsample,ts)
+  subroutine sfox_init(mm0,nn0,kk0,itu,fspread,delay,fsample,ns0)
 
     character*2 itu
     integer isps(54)
@@ -18,19 +18,17 @@ contains
 
     MM=mm0              !Bits per symbol
     NQ=2**MM            !Q, number of MFSK tones
-    NN=nn0              !Number of channel symbols
+    NN=nn0              !Codeword length
-    KK=kk0              !Information symbols
+    KK=kk0              !Number of information symbols
-    ND1=25              !Data symbols before sync 
+    NS=ns0              !Number of sync symbols
-    ND2=NN-ND1          !Data symbols after sync 
+    NDS=NN+NS           !Total number of channel symbols
     NFZ=3               !First zero
 
-    jsps=nint((12.8-ts)*fsample/NN)
+    jsps=nint(12.8*fsample/NDS)
     iloc=minloc(abs(isps-jsps))
     NSPS=isps(iloc(1))  !Samples per symbol
-    NS=nint(ts*fsample/NSPS)
-    if(mod(NS,2).eq.1) NS=NS+1
     NSYNC=NS*NSPS       !Samples in sync waveform
-    NZ=NSPS*(NN+NS)     !Samples in full Tx waveform
+    NZ=NSPS*NDS         !Samples in full Tx waveform
     NFFT=32768          !Length of FFT for sync waveform
     NFFT1=2*NSPS        !Length of FFTs for symbol spectra
 

lib/superfox/sfoxtest.f90

@@ -10,7 +10,7 @@ program sfoxtest
   type(hdr) h                            !Header for .wav file
   integer*2 iwave(NMAX)                  !Generated i*2 waveform
   integer param(0:8)
-  integer isync(50)
+  integer isync(44)
   real*4 xnoise(NMAX)                    !Random noise
   real*4 dat(NMAX)                       !Generated real data
   complex cdat(NMAX)                     !Generated complex waveform
@@ -31,21 +31,24 @@ program sfoxtest
   logical hard_sync
   character fname*17,arg*12,itu*2
 
-! Shortcut: this is OK for NS <= 24 only
+  data isync/ 1,   2,   5,  11,  19,  24,  26,  28,  29,  35,  &
-  data isync(1:24)/ 21, 94, 55,125, 94, 29, 11, 64, 63,  6,  &
+             39,  48,  51,  53,  55,  56,  66,  71,  74,  78,  &
-                    59, 67, 52, 39,116, 98, 67, 68, 75, 87,  &
+             80,  82,  84,  85,  92,  98, 103, 107, 109, 111,  &
-                    116, 22,113,105/
+            116, 122, 130, 131, 134, 136, 137, 140, 146, 154,  &
+            159, 161, 163, 165/
+
+
 
   nargs=iargc()
   if(nargs.ne.11) then
-     print*,'Usage:   sfoxtest  f0   DT  ITU M  N   K ts v hs nfiles snr'
+     print*,'Usage:   sfoxtest  f0   DT  ITU M  N   K NS v hs nfiles snr'
-     print*,'Example: sfoxtest 1500 0.15  MM 7 127 48  3 0  F   10   -10'
+     print*,'Example: sfoxtest 1500 0.15  MM 7 127 48 33 0  F   10   -10'
      print*,'         f0=0 means f0, DT will assume suitable random values'
      print*,'         LQ: Low Latitude Quiet'
      print*,'         MM: Mid Latitude Moderate'
      print*,'         HD: High Latitude Disturbed'
      print*,'         ... and similarly for LM LD MQ MD HQ HM'
-     print*,'         ts: approximate sync duration (s)'
+     print*,'         NS: number of sync symbols'
      print*,'         v=1 for .wav files, 2 for verbose output, 3 for both'
      print*,'         hs = T for hard-wired sync'
      print*,'         snr=0 means loop over SNRs'
@@ -63,7 +66,7 @@ program sfoxtest
   call getarg(6,arg)
   read(arg,*) kk0
   call getarg(7,arg)
-  read(arg,*) ts
+  read(arg,*) ns0
   call getarg(8,arg)
   read(arg,*) nv
   call getarg(9,arg)
@@ -77,7 +80,7 @@ program sfoxtest
   call timer('sfoxtest',0)
 
   fsample=12000.0                   !Sample rate (Hz)
-  call sfox_init(mm0,nn0,kk0,itu,fspread,delay,fsample,ts)
+  call sfox_init(mm0,nn0,kk0,itu,fspread,delay,fsample,ns0)
   baud=fsample/NSPS
   tsym=1.0/baud
   bw=NQ*baud
@@ -107,7 +110,6 @@ program sfoxtest
   baud=fsample/nsps                 !Keying rate, 11.719 baud for nsps=1024
   bandwidth_ratio=2500.0/fsample
   fgood0=1.0
-!  isync(NS-3:NS)=NQ/2               !Set last few sync symbols to NQ/2
 
 ! Generate a message
   msg0=0