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Compute signal power, noise power, and SNR_2500 explicitly in ft8sim.f90.

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This commit is contained in:
Joe Taylor 2024-02-19 13:23:42 -05:00
parent ec0c31d849
commit fb19d27602
1 changed files with 13 additions and 3 deletions
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16
lib/ft8/ft8sim.f90
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@ -101,14 +101,24 @@ program ft8sim_gfsk
wave=imag(c) wave=imag(c)
peak=maxval(abs(wave)) peak=maxval(abs(wave))
nslots=1 nslots=1
psig=0.
pnoise=0.
if(snrdb.lt.90) then if(snrdb.lt.90) then
do i=1,NMAX !Add gaussian noise at specified SNR do i=1,NMAX !Add gaussian noise at specified SNR
xnoise=gran() xnoise=gran()
if(i.ge.6001 .and. i.le.157692) then
psig=psig + wave(i)*wave(i) !Signal power
pnoise=pnoise + xnoise*xnoise !Noise power in signal interval
endif
wave(i)=wave(i) + xnoise wave(i)=wave(i) + xnoise
enddo enddo
endif endif
! Noise power in signal interval and 2500 Hz bandwidth:
pnoise=bandwidth_ratio*pnoise
snr_2500=db(psig/pnoise) !SNR in 2500 Hz bandwidth
gain=100.0 gain=100.0
if(snrdb.lt.90.0) then if(snrdb.lt.90.0) then
wave=gain*wave wave=gain*wave
@ -125,7 +135,7 @@ program ft8sim_gfsk
open(10,file=fname,status='unknown',access='stream') open(10,file=fname,status='unknown',access='stream')
write(10) h,iwave !Save to *.wav file write(10) h,iwave !Save to *.wav file
close(10) close(10)
write(*,1110) ifile,xdt,f0,snrdb,fname write(*,1110) ifile,xdt,f0,snrdb,fname,snr_2500
1110 format(i4,f7.2,f8.2,f7.1,2x,a17) 1110 format(i4,f7.2,f8.2,f7.1,2x,a17,f8.2)
enddo enddo
999 end program ft8sim_gfsk 999 end program ft8sim_gfsk