Add optional Rayleigh fading to jt65sim.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6132 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/Makefile.jt65

@@ -58,7 +58,7 @@ jt65: $(OBJS7) libjt9.a libsfrsd.a
 
 OBJS2 = jt65sim.o wavhdr.o
 jt65sim: $(OBJS2) libjt9.a
-	$(FC) -o jt65sim $(OBJS2) -L. -L/opt/local/lib -ljt9
+	$(FC) -o jt65sim $(OBJS2) -L. -L/opt/local/lib -ljt9 -lfftw3f
 	$(CP) jt65sim $(EXE_DIR)
 
 init_rs.o: init_rs.c

lib/jt65sim.f90

@@ -4,16 +4,21 @@ program jt65sim
 
   use wavhdr
   use packjt
-  parameter (NTMAX=54)
+  parameter (NMAX=54*12000)              ! = 648,000
-  parameter (NMAX=NTMAX*12000)
+  parameter (NFFT=10*65536,NH=NFFT/2)
-  type(hdr) h
+  type(hdr) h                            !Header for .wav file
   integer*2 iwave(NMAX)                  !Generated waveform
   integer*4 itone(126)                   !Channel symbols (values 0-65)
-  integer dgen(12),sent(63)
+  integer dgen(12)                       !Twelve 6-bit data symbols
-  real*4 dat(NMAX)
+  integer sent(63)                       !RS(63,12) codeword
+  real*4 xnoise(NMAX)                    !Generated random noise
+  real*4 dat(NMAX)                       !Generated real data
+  complex cdat(NMAX)                     !Generated complex waveform
+  complex cspread(0:NFFT-1)              !Complex amplitude for Rayleigh fading
+  complex z
   real*8 f0,dt,twopi,phi,dphi,baud,fsample,freq,sps
   character msg*22,arg*8,fname*11,csubmode*1
-  integer nprc(126)
+  integer nprc(126)                                      !Sync pattern
   data nprc/1,0,0,1,1,0,0,0,1,1,1,1,1,1,0,1,0,1,0,0,  &
             0,1,0,1,1,0,0,1,0,0,0,1,1,1,0,0,1,1,1,1,  &
             0,1,1,0,1,1,1,1,0,0,0,1,1,0,1,0,1,0,1,1,  &
@@ -24,8 +29,8 @@ program jt65sim
 
   nargs=iargc()
   if(nargs.ne.5) then
-     print*,'Usage:   jt65sim mode nRay nsigs SNR nfiles'
+     print*,'Usage:   jt65sim mode nsigs fspread SNR nfiles'
-     print*,'Example: jt65sim   B    0    10  -24    1'
+     print*,'Example: jt65sim   B    10    0.0   -24    1'
      print*,'Enter SNR = 0 to generate a range of SNRs.'
      go to 999
   endif
@@ -36,40 +41,39 @@ program jt65sim
   if(csubmode.eq.'B') mode65=2
   if(csubmode.eq.'C') mode65=4
   call getarg(2,arg)
-  read(arg,*) nRay                   !1 ==> Rayleigh fading
-  call getarg(3,arg)
   read(arg,*) nsigs                  !Number of signals in each file
+  call getarg(3,arg)
+  read(arg,*) fspread                !Doppler spread (Hz)
   call getarg(4,arg)
   read(arg,*) snrdb                  !S/N in dB (2500 hz reference BW)
   call getarg(5,arg)
   read(arg,*) nfiles                 !Number of files     
 
-  rmsdb=25.
+  rms=100.
-  rms=10.0**(0.05*rmsdb)
   fsample=12000.d0                   !Sample rate (Hz)
   dt=1.d0/fsample                    !Sample interval (s)
   twopi=8.d0*atan(1.d0)
-  npts=54*12000
+  npts=54*12000                      !Total samples in .wav file
-  baud=11025.d0/4096.d0
+  baud=11025.d0/4096.d0              !Keying rate
   sps=12000.d0/baud                  !Samples per symbol, at fsample=12000 Hz
-  nsym=126
+  nsym=126                           !Number of channel symbols
   h=default_header(12000,npts)
+  dfsig=2000.0/nsigs                 !Freq spacing between sigs in file (Hz)
 
-  do ifile=1,nfiles                  !Loop over all files
+  do ifile=1,nfiles                  !Loop over requested number of files
      write(fname,1002) ifile         !Output filename
 1002 format('000000_',i4.4)
      open(10,file=fname//'.wav',access='stream',status='unknown')
 
+     xnoise=0.
+     cdat=0.
      if(snrdb.lt.90) then
         do i=1,npts
-           dat(i)=gran()             !Generate AWGN
+           xnoise(i)=gran()          !Generate gaussian noise
         enddo
-     else
-        dat(1:npts)=0.
      endif
 
-     dfsig=2000.0/nsigs
+     do isig=1,nsigs                        !Generate requested number of sigs
-     do isig=1,nsigs
         if(mod(nsigs,2).eq.0) f0=1500.0 + dfsig*(isig-0.5-nsigs/2)
         if(mod(nsigs,2).eq.1) f0=1500.0 + dfsig*(isig-(nsigs+1)/2)
         nsnr=nint(snrdb)
@@ -80,12 +84,12 @@ program jt65sim
 1010    format('K1ABC W9XYZ ',i3.2)
 
         call packmsg(msg,dgen,itype)        !Pack message into 12 six-bit bytes
-        call rs_encode(dgen,sent)           !RS encode
+        call rs_encode(dgen,sent)           !Encode using RS(63,12)
         call interleave63(sent,1)           !Interleave channel symbols
         call graycode65(sent,63,1)          !Apply Gray code
 
         k=0
-        do j=1,nsym
+        do j=1,nsym                         !Insert sync and data into itone()
            if(nprc(j).eq.0) then
               k=k+1
               itone(j)=sent(k)+2
@@ -95,7 +99,6 @@ program jt65sim
         enddo
 
         sig=10.0**(0.05*nsnr)
-!        sig=1.122*sig
         if(nsnr.gt.90.0) sig=1.0
         write(*,1020) ifile,isig,f0,csubmode,nsnr,sig,msg
 1020    format(i4,i4,f10.3,1x,a1,i5,f8.4,2x,a22)
@@ -104,7 +107,7 @@ program jt65sim
         dphi=0.d0
         k=12000                             !Start audio at t = 1.0 s
         isym0=-99
-        do i=1,npts
+        do i=1,npts                         !Add this signal into cdat()
            isym=nint(i/sps)+1
            if(isym.gt.nsym) exit
            if(isym.ne.isym0) then
@@ -115,15 +118,74 @@ program jt65sim
            phi=phi + dphi
            if(phi.gt.twopi) phi=phi-twopi
            xphi=phi
+           z=cmplx(cos(xphi),sin(xphi))
            k=k+1
-           dat(k)=dat(k) + sig*sin(xphi)
+           cdat(k)=cdat(k) + sig*z
         enddo
      enddo
 
+     if(fspread.ne.0) then                  !Apply specified Doppler spread
+        df=12000.0/nfft
+        twopi=8*atan(1.0)
+        cspread(0)=1.0
+        cspread(NH)=0.
+
+        do i=1,NH
+           f=i*df
+           x=-f/fspread
+           z=0.
+           a=0.
+           if(x.lt.50.0) then
+              a=sqrt(exp(-x*x))
+              call random_number(r1)
+              phi1=twopi*r1
+              z=a*cmplx(cos(phi1),sin(phi1))
+           endif
+           cspread(i)=z
+           z=0.
+           if(x.lt.50.0) then
+              call random_number(r2)
+              phi2=twopi*r2
+              z=a*cmplx(cos(phi2),sin(phi2))
+           endif
+           cspread(NFFT-i)=z
+        enddo
+
+        do i=0,NFFT-1
+           f=i*df
+           if(i.gt.NH) f=(i-nfft)*df
+           s=real(cspread(i))**2 + aimag(cspread(i))**2
+!          write(13,3000) i,f,s,cspread(i)
+!3000      format(i5,f10.3,3f12.6)
+        enddo
+!        s=real(cspread(0))**2 + aimag(cspread(0))**2
+!        write(13,3000) 1024,0.0,s,cspread(0)
+
+        call four2a(cspread,NFFT,1,1,1)             !Transform to time domain
+
+        sum=0.
+        do i=0,NFFT-1
+           p=real(cspread(i))**2 + aimag(cspread(i))**2
+           sum=sum+p
+        enddo
+        avep=sum/NFFT
+        fac=sqrt(1.0/avep)
+        cspread=fac*cspread                   !Normalize to constant avg power
+        cdat=cspread(1:npts)*cdat             !Apply Rayleigh fading
+
+!        do i=0,NFFT-1
+!           p=real(cspread(i))**2 + aimag(cspread(i))**2
+!           write(14,3010) i,p,cspread(i)
+!3010       format(i8,3f12.6)
+!        enddo
+
+     endif
+
+     dat=aimag(cdat) + xnoise                 !Add the generated noise
      fac=32767.0/nsigs
      if(snrdb.ge.90.0) iwave(1:npts)=nint(fac*dat(1:npts))
      if(snrdb.lt.90.0) iwave(1:npts)=nint(rms*dat(1:npts))
-     write(10) h,iwave(1:npts)
+     write(10) h,iwave(1:npts)                !Save the .wav file
      close(10)
   enddo
 

lib/wsprd/Makefile

@@ -1,9 +1,10 @@
 CC = gcc
-#CC = clang
+#CC = clang-3.5
 FC = gfortran
 
 CFLAGS= -I/usr/include -Wall -Wno-missing-braces -O3 -ffast-math
 LDFLAGS = -L/usr/lib
+FFLAGS =  -O2 -Wall -Wno-conversion
 LIBS = -lfftw3 -lm
 
 # Default rules