WSJT-X/lib/fsk4hf/wspr_fsk8_sim.f90

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Fortran
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program wspr_fsk8_sim
! Generate simulated data for a 4-minute "WSPR-LF" mode using 8-FSK.
! Output is saved to a *.wav file.
use wavhdr
include 'wspr_fsk8_params.f90' !Set various constants
type(hdr) h !Header for .wav file
character arg*12,fname*16
character msg*22,msgsent*22
integer itone(NN)
integer*2 iwave(NMAX) !Generated full-length waveform
! Get command-line argument(s)
nargs=iargc()
if(nargs.ne.5) then
print*,'Usage: wspr_fsk8_sim "message" f0 DT nfiles snr'
print*,'Example: wspr_fsk8_sim "K1ABC FN42 30" 1640 0.0 10 -33'
go to 999
endif
call getarg(1,msg) !Message to be transmitted
call getarg(2,arg)
read(arg,*) f0 !Freq relative to WSPR-band center (Hz)
call getarg(3,arg)
read(arg,*) xdt !Time offset from nominal (s)
call getarg(4,arg)
read(arg,*) nfiles !Number of files
call getarg(5,arg)
read(arg,*) snrdb !SNR_2500
twopi=8.0*atan(1.0)
fs=12000.0/NDOWN !Sample rate after downsampling
dt=1.0/fs !Sample interval (s)
tt=NSPS*dt !Duration of symbols (s)
baud=1.0/tt !Keying rate
bw=8*baud
txt=NZ*dt !Transmission length (s)
bandwidth_ratio=2500.0/(fs/2.0)
sig=sqrt(bandwidth_ratio) * 10.0**(0.05*snrdb)
if(snrdb.gt.90.0) sig=1.0
txt=NN*NSPS0/12000.0
call genwspr_fsk8(msg,msgsent,itone) !Encode the message, get itone
write(*,1000) f0,xdt,txt,snrdb,bw,msgsent
1000 format('f0:',f9.3,' DT:',f6.2,' TxT:',f6.1,' SNR:',f6.1, &
' BW:',f4.1,2x,a22)
do ifile=1,nfiles
call wspr_fsk8_wav(baud,xdt,f0,itone,snrdb,iwave)
h=default_header(12000,NMAX)
write(fname,1102) ifile
1102 format('000000_',i4.4,'.wav')
open(10,file=fname,status='unknown',access='stream')
write(10) h,iwave !Save to *.wav file
close(10)
write(*,1110) ifile,xdt,f0,snrdb,fname
1110 format(i4,f7.2,f8.2,f7.1,2x,a16)
enddo
999 end program wspr_fsk8_sim