ft2sim now creates a GFSK waveform with BT=1.0. It also adds raised cosine ramp up and down at the beginning and end of the transmission.

lib/fsk4hf/ft2d.f90

@@ -93,7 +93,7 @@ program ft2d
         ibest=-1
         sybest=-99.
         dfbest=-1.
-        do if=-15,+15
+        do if=-30,+30
            df=if
            a=0.
            a(1)=-df
@@ -120,8 +120,6 @@ program ft2d
            enddo 
         enddo
 
-!dfbest=0.0
-!ibest=187
         a=0.
         a(1)=-dfbest
         call twkfreq1(c2,NMAX/16,fs,a,cb)
@@ -197,7 +195,6 @@ program ft2d
               call bpdecode128_90(llr2,apmask,max_iterations,message77,cw,nharderror,niterations)
               if(nharderror.ge.0) exit 
            enddo
-           nhardmin=-1
            if(sum(message77).eq.0) cycle
            if( nharderror.ge.0 ) then
               write(c77,'(77i1)') message77(1:77)
@@ -212,8 +209,8 @@ program ft2d
               nsnr=nint(xsnr)
               freq=f0+dfbest
 1210          format(a11,2i4,f6.2,f12.7,2x,a22,i3)
-              write(*,1212) datetime(8:11),nsnr,ibest/750.0,freq,message,'*',idf,nseq,ijitter,nharderror,nhardmin
-1212          format(a4,i4,f5.1,f11.1,2x,a22,a1,i5,i5,i5,i5,i5)
+              write(*,1212) datetime(8:11),nsnr,ibest/750.0,freq,message,'*',nseq,nharderror
+1212          format(a4,i4,f5.1,f11.1,2x,a22,a1,i5,i5)
               goto 888
            endif
         enddo ! nseq

lib/fsk4hf/ft2sim.f90

@@ -1,3 +1,10 @@
+real function gfsk_pulse(b,t)
+pi=4.*atan(1.0)
+c=pi*sqrt(2.0/log(2.0))
+gfsk_pulse=0.5*(erf(c*b*(t+0.5))-erf(c*b*(t-0.5)))
+return
+end function gfsk_pulse
+
 program ft2sim
 
 ! Generate simulated signals for experimental "FT2" mode 
@@ -13,10 +20,12 @@ program ft2sim
   complex c0(0:NMAX-1)
   complex c(0:NMAX-1)
   real wave(NMAX)
+  real dphi(0:NMAX-1)
+  real pulse(480)               
   integer itone(NN)
   integer*1 msgbits(77)
   integer*2 iwave(NMAX)                  !Generated full-length waveform
-
+  
 ! Get command-line argument(s)
   nargs=iargc()
   if(nargs.ne.8) then
@@ -42,12 +51,6 @@ program ft2sim
   call getarg(8,arg)
   read(arg,*) snrdb                      !SNR_2500
 
-  nsig=1
-  if(f0.lt.100.0) then
-     nsig=f0
-     f0=1500
-  endif
-
   nfiles=abs(nfiles)
   twopi=8.0*atan(1.0)
   fs=12000.0                             !Sample rate (Hz)
@@ -55,8 +58,8 @@ program ft2sim
   hmod=0.8                               !Modulation index (0.5 is MSK, 1.0 is FSK)
   tt=NSPS*dt                             !Duration of symbols (s)
   baud=1.0/tt                            !Keying rate (baud)
-  bw=1.5*baud                            !Occupied bandwidth (Hz)
   txt=NZ*dt                              !Transmission length (s)
+
   bandwidth_ratio=2500.0/(fs/2.0)
   sig=sqrt(2*bandwidth_ratio) * 10.0**(0.05*snrdb)
   if(snrdb.gt.90.0) sig=1.0
@@ -70,9 +73,8 @@ program ft2sim
   call genft2(msg37,0,msgsent37,itone,itype)
   write(*,*)  
   write(*,'(a9,a37,3x,a7,i1,a1,i1)') 'Message: ',msgsent37,'i3.n3: ',i3,'.',n3
-  write(*,1000) f0,xdt,txt,snrdb,bw
-1000 format('f0:',f9.3,'   DT:',f6.2,'   TxT:',f6.1,'   SNR:',f6.1,    &
-       '  BW:',f5.1)
+  write(*,1000) f0,xdt,txt,snrdb
+1000 format('f0:',f9.3,'   DT:',f6.2,'   TxT:',f6.1,'   SNR:',f6.1)
   write(*,*)  
   if(i3.eq.1) then
     write(*,*) '         mycall                         hiscall                    hisgrid'
@@ -88,21 +90,41 @@ program ft2sim
 
   call sgran()
 
+! The filtered frequency pulse 
+  do i=1,480
+     tt=(i-240.5)/160.0
+     pulse(i)=gfsk_pulse(1.0,tt)
+  enddo
+
+! Define the instantaneous frequency waveform
+  dphi_peak=twopi*(hmod/2.0)/real(NSPS)
+  dphi=0.0 
+  do j=1,NN         
+     ib=(j-1)*160
+     ie=ib+480-1
+     dphi(ib:ie)=dphi(ib:ie)+dphi_peak*pulse*(2*itone(j)-1)
+  enddo
+
+  phi=0.0
+  c0=0.0
+  dphi=dphi+twopi*f0*dt
+  do j=0,NMAX-1
+     c0(j)=cmplx(cos(phi),sin(phi))
+     phi=mod(phi+dphi(j),twopi)
+  enddo 
+ 
+  c0(0:159)=c0(0:159)*(1.0-cos(twopi*(/(i,i=0,159)/)/320.0) )/2.0
+  c0(144*160:144*160+159)=c0(144*160:144*160+159)*(1.0+cos(twopi*(/(i,i=0,159)/)/320.0 ))/2.0
+  c0(145*160:)=0.
+
+  k=nint((xdt+0.25)/dt)
+  c0=cshift(c0,-k)
+  ia=k
+  
   do ifile=1,nfiles
-     k=nint((xdt+0.25)/dt)
-     ia=k
-     phi=0.0 
-     c0=0.0
-     do j=1,NN                             !Generate complex waveform
-        dphi=twopi*(f0*dt+(hmod/2.0)*(2*itone(j)-1)/real(NSPS))
-        do i=1,NSPS
-           if(k.ge.0 .and. k.lt.NMAX) c0(k)=cmplx(cos(phi),sin(phi))
-           k=k+1
-           phi=mod(phi+dphi,twopi)
-        enddo
-     enddo
-     if(fspread.ne.0.0 .or. delay.ne.0.0) call watterson(c0,NMAX,NWAVE,fs,delay,fspread)
-     c=sig*c0
+     c=c0
+     if(fspread.ne.0.0 .or. delay.ne.0.0) call watterson(c,NMAX,NWAVE,fs,delay,fspread)
+     c=sig*c
   
      ib=k
      wave=real(c)