WSJT-X/lib/fst4/fst4sim.f90

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Fortran
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program fst4sim
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! Generate simulated signals for experimental slow FT4 mode
use wavhdr
use packjt77
include 'fst4_params.f90' !Set various constants
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type(hdr) h !Header for .wav file
logical*1 wspr_hint
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character arg*12,fname*17
character msg37*37,msgsent37*37,c77*77
complex, allocatable :: c0(:)
complex, allocatable :: c(:)
real, allocatable :: wave(:)
integer hmod
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integer itone(NN)
integer*1 msgbits(101)
integer*2, allocatable :: iwave(:) !Generated full-length waveform
! Get command-line argument(s)
nargs=iargc()
if(nargs.ne.9) then
print*,'Need 9 arguments, got ',nargs
print*,'Usage: fst4sim "message" TRsec f0 DT fdop del nfiles snr W'
print*,'Examples: fst4sim "K1JT K9AN EN50" 60 1500 0.0 0.1 1.0 10 -15 F'
print*,'W (T or F) argument is hint to encoder to use WSPR message when there is abiguity'
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go to 999
endif
call getarg(1,msg37) !Message to be transmitted
call getarg(2,arg)
read(arg,*) nsec !TR sequence length, seconds
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call getarg(3,arg)
read(arg,*) f00 !Frequency (only used for single-signal)
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call getarg(4,arg)
read(arg,*) xdt !Time offset from nominal (s)
call getarg(5,arg)
read(arg,*) fspread !Watterson frequency spread (Hz)
call getarg(6,arg)
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read(arg,*) delay !Watterson delay (ms)
call getarg(7,arg)
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read(arg,*) nfiles !Number of files
call getarg(8,arg)
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read(arg,*) snrdb !SNR_2500
call getarg(9,arg)
read(arg,*) wspr_hint !0:break ties as 77-bit 1:break ties as 50-bit
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nfiles=abs(nfiles)
twopi=8.0*atan(1.0)
fs=12000.0 !Sample rate (Hz)
dt=1.0/fs !Sample interval (s)
nsps=0
if(nsec.eq.15) nsps=720
if(nsec.eq.30) nsps=1680
if(nsec.eq.60) nsps=3888
if(nsec.eq.120) nsps=8200
if(nsec.eq.300) nsps=21504
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if(nsec.eq.900) nsps=66560
if(nsec.eq.1800) nsps=134400
if(nsps.eq.0) then
print*,'Invalid TR sequence length.'
go to 999
endif
baud=12000.0/nsps !Keying rate (baud)
nmax=nsec*12000
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nz=nsps*NN
txt=nz*dt !Transmission length (s)
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tt=nsps*dt !Duration of symbols (s)
nwave=max(nmax,(NN+2)*nsps)
allocate( c0(0:nwave-1) )
allocate( c(0:nwave-1) )
allocate( wave(nwave) )
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allocate( iwave(nmax) )
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
if(wspr_hint) then
i3=0
n3=6
else
i3=-1
n3=-1
endif
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call pack77(msg37,i3,n3,c77)
if(i3.eq.0.and.n3.eq.6) iwspr=1
call genfst4(msg37,0,msgsent37,msgbits,itone,iwspr)
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write(*,*)
write(*,'(a9,a37,a3,L2,a7,i2)') 'Message: ',msgsent37,'W:',wspr_hint,' iwspr:',iwspr
write(*,1000) f00,xdt,txt,snrdb
1000 format('f0:',f9.3,' DT:',f6.2,' TxT:',f6.1,' SNR:',f6.1)
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write(*,*)
if(i3.eq.1) then
write(*,*) ' mycall hiscall hisgrid'
write(*,'(28i1,1x,i1,1x,28i1,1x,i1,1x,i1,1x,15i1,1x,3i1)') msgbits(1:77)
else
write(*,'(a14)') 'Message bits: '
write(*,'(77i1,1x,24i1)') msgbits
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endif
write(*,*)
write(*,'(a17)') 'Channel symbols: '
write(*,'(10i1)') itone
write(*,*)
! call sgran()
fsample=12000.0
hmod=1
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icmplx=1
f0=f00+1.5*hmod*baud
call gen_fst4wave(itone,NN,nsps,nwave,fsample,hmod,f0,icmplx,c0,wave)
k=nint((xdt+1.0)/dt)
if(nsec.eq.15) k=nint((xdt+0.5)/dt)
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c0=cshift(c0,-k)
if(k.gt.0) c0(0:k-1)=0.0
if(k.lt.0) c0(nmax+k:nmax-1)=0.0
do ifile=1,nfiles
c=c0
if(fspread.gt.0.0 .or. delay.ne.0.0) call watterson(c,nwave,NZ,fs,delay,fspread)
if(fspread.lt.0.0) call lorentzian_fading(c,nwave,fs,-fspread)
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c=sig*c
wave=aimag(c)
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if(snrdb.lt.90) then
do i=1,nmax !Add gaussian noise at specified SNR
xnoise=gran()
wave(i)=wave(i) + xnoise
enddo
endif
gain=100.0
if(snrdb.lt.90.0) then
wave=gain*wave
else
datpk=maxval(abs(wave))
fac=32766.9/datpk
wave=fac*wave
endif
if(any(abs(wave).gt.32767.0)) print*,"Warning - data will be clipped."
iwave=nint(wave(:size(iwave)))
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h=default_header(12000,nmax)
if(nmax/12000.le.30) then
write(fname,1102) ifile
1102 format('000000_',i6.6,'.wav')
else
write(fname,1104) ifile
1104 format('000000_',i4.4,'.wav')
endif
open(10,file=trim(fname),status='unknown',access='stream')
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write(10) h,iwave !Save to *.wav file
close(10)
write(*,1110) ifile,xdt,f00,snrdb,fname
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1110 format(i4,f7.2,f8.2,f7.1,2x,a17)
enddo
999 end program fst4sim