subroutine foxgen() ! Called from MainWindow::foxTxSequencer() to generate the Tx waveform in ! FT8 Fox mode. The Tx message can contain up to 5 "slots", each carrying ! its own FT8 signal. ! Encoded messages can be of the form "HoundCall FoxCall rpt" (a standard FT8 ! message with i3bit=0) or "HoundCall_1 RR73; HoundCall_2 rpt", ! a new message type with i3bit=1. The waveform is generated with ! fsample=48000 Hz; it is compressed to reduce the PEP-to-average power ratio, ! with (currently disabled) filtering afterware to reduce spectral growth. ! Input message information is provided in character array cmsg(5), in ! common/foxcom/. The generated wave(NWAVE) is passed back in the same ! common block. use crc parameter (NN=79,ND=58,KK=87,NSPS=4*1920) parameter (NWAVE=NN*NSPS,NFFT=614400,NH=NFFT/2) character*32 cmsg character*22 msg,msgsent character*6 mygrid character*87 cbits character*88 cb88 logical bcontest,checksumok integer itone(NN) integer icos7(0:6) integer*1 msgbits(KK),codeword(3*ND),msgbits2 integer*1, target:: i1Msg8BitBytes(11) integer*1, target:: mycall real x(NFFT),y(NFFT) real*8 dt,twopi,f0,fstep,dfreq,phi,dphi complex cx(0:NH),cy(0:NH) common/foxcom/wave(NWAVE),nslots,i3bit(5),cmsg(5),mycall(6) common/foxcom2/itone2(NN),msgbits2(KK) equivalence (x,cx),(y,cy) data icos7/2,5,6,0,4,1,3/ !Costas 7x7 tone pattern bcontest=.false. fstep=60.d0 dfreq=6.25d0 dt=1.d0/48000.d0 twopi=8.d0*atan(1.d0) wave=0. mygrid=' ' irpt=0 do n=1,nslots i3b=i3bit(n) if(i3b.eq.0) then msg=cmsg(n)(1:22) !Stansard FT8 message else i1=index(cmsg(n),' ') !Special Fox message i2=index(cmsg(n),';') i3=index(cmsg(n),'<') i4=index(cmsg(n),'>') msg=cmsg(n)(1:i1)//cmsg(n)(i2+1:i3-2)//' ' read(cmsg(n)(i4+2:i4+4),*) irpt endif call genft8(msg,mygrid,bcontest,0,msgsent,msgbits,itone) if(i3b.eq.1) then icrc10=crc10(c_loc(mycall),6) nrpt=irpt+30 write(cbits,1001) msgbits(1:56),icrc10,nrpt,i3b,0 1001 format(56b1.1,b10.10,b6.6,b3.3,b12.12) read(cbits,1002) msgbits 1002 format(87i1) cb88=cbits//'0' read(cb88,1003) i1Msg8BitBytes(1:11) 1003 format(11b8) icrc12=crc12(c_loc(i1Msg8BitBytes),11) print*,'BB',icrc10,nrpt,i3b,icrc12 write(cbits,1001) msgbits(1:56),icrc10,nrpt,i3b,icrc12 read(cbits,1002) msgbits call encode174(msgbits,codeword) !Encode the test message ! Message structure: S7 D29 S7 D29 S7 itone(1:7)=icos7 itone(36+1:36+7)=icos7 itone(NN-6:NN)=icos7 k=7 do j=1,ND i=3*j -2 k=k+1 if(j.eq.30) k=k+7 itone(k)=codeword(i)*4 + codeword(i+1)*2 + codeword(i+2) enddo endif ! Make copies of itone() and msgbits() for ft8sim itone2=itone msgbits2=msgbits f0=1800.d0 + fstep*(n-1) phi=0.d0 k=0 do j=1,NN f=f0 + dfreq*itone(j) dphi=twopi*f*dt do ii=1,NSPS k=k+1 phi=phi+dphi xphi=phi wave(k)=wave(k)+sin(xphi) enddo enddo enddo sqx=0. do i=1,NWAVE sqx=sqx + wave(i)*wave(i) enddo sigmax=sqrt(sqx/NWAVE) wave=wave/sigmax !Force rms=1.0 do i=1,NWAVE wave(i)=h1(wave(i)) !Compress the waveform enddo fac=1.0/maxval(abs(wave)) !Set maxval = 1.0 wave=fac*wave if(NWAVE.ne.-99) go to 100 !### Omit filtering, for now ### x(1:k)=wave x(k+1:)=0. call four2a(x,nfft,1,-1,0) nadd=64 k=0 df=48000.0/NFFT rewind(29) do i=1,NH/nadd - 1 sx=0. ! sy=0. do j=1,nadd k=k+1 sx=sx + real(cx(k))**2 + aimag(cx(k))**2 ! sy=sy + real(cy(k))**2 + aimag(cy(k))**2 enddo freq=df*(k-nadd/2+0.5) write(29,1022) freq,sx,sy,db(sx)-90.0,db(sy)-90.0 1022 format(f10.3,2e12.3,2f10.3) if(freq.gt.3000.0) exit enddo flush(29) 100 continue return end subroutine foxgen real function h1(x) ! sigma=1.0/sqrt(2.0) sigma=1.0 xlim=sigma/sqrt(6.0) ax=abs(x) sgnx=1.0 if(x.lt.0) sgnx=-1.0 if(ax.le.xlim) then h1=x else z=exp(1.0/6.0 - (ax/sigma)**2) h1=sgnx*sqrt(6.0)*sigma*(2.0/3.0 - 0.5*z) endif return end function h1