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https://github.com/saitohirga/WSJT-X.git
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79 lines
2.3 KiB
Fortran
79 lines
2.3 KiB
Fortran
subroutine sfox_wave_gfsk(fname)
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! Called by WSJT-X when it's time for SuperFox to transmit. Reads array
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! itone(1:151) from disk file 'sfox_2.dat' in the writable data directory.
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! Generates a GFSK waveform with short ramp-up and ramp-down symbols of
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! duration NSPS/BT at the beginning and end of the waveform.
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parameter (NWAVE=(160+2)*134400*4) !Max WSJT-X waveform (FST4-1800 at 48kHz)
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parameter (NSYM=151,NSPS=1024*4)
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parameter (NPTS=(NSYM+2)*NSPS)
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parameter (BT=8)
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character*(*) fname
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integer itone(151)
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real*8 dt,twopi,f0,baud,phi,dphi_peak
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real*8 dphi(0:NPTS-1)
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real*8 pulse(3*NSPS)
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logical first/.true./
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common/foxcom/wave(NWAVE)
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save first,twopi,dt,hmod,dphi_peak,pulse
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if(first) then
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fsample=48000.0
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twopi=8.d0*atan(1.d0)
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dt=1.d0/fsample
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hmod=1.0
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dphi_peak=twopi*hmod/real(NSPS)
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do i=1,3*NSPS
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tt=(i-1.5*NSPS)/real(NSPS)
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pulse(i)=gfsk_pulse(BT,tt)
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enddo
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first=.false.
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endif
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wave=0.
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open(25,file=trim(fname),status='unknown',err=999)
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read(25,'(20i4)',err=999,end=999) itone
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close(25)
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if(itone(1).lt.0 .or. itone(1).gt.128) go to 999
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! Generate the SuperFox waveform.
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dphi=0.d0
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do j=1,NSYM
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ib=(j-1)*NSPS
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ie=ib+3*NSPS-1
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dphi(ib:ie)=dphi(ib:ie)+dphi_peak*pulse(1:3*NSPS)*itone(j)
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enddo
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dphi(0:2*NSPS-1)=dphi(0:2*NSPS-1)+dphi_peak*itone(1)*pulse(NSPS+1:3*NSPS)
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dphi(NSYM*NSPS:(NSYM+2)*NSPS-1)=dphi(NSYM*NSPS:(NSYM+2)*NSPS-1)+dphi_peak*itone(NSYM)*pulse(1:2*NSPS)
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phi=0.d0
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f0=750.0d0
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dphi=dphi+twopi*f0*dt
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k=0
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do j=1,NSPS*(NSYM+2)-1
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k=k+1
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wave(k)=sin(phi)
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phi=phi+dphi(j)
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enddo
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! Add raised cosine ramps at the beginning and end of the waveform.
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! Since the modulator expects an integral number of symbols, dummy
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! symbols are added to the beginning and end of the waveform to
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! hold the ramps. All but nramp of the samples in each dummy
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! symbol will be zero.
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nramp=NSPS/BT
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wave(1:NSPS-nramp)=0.0
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wave(NSPS-nramp+1:NSPS)=wave(NSPS-nramp+1:NSPS) * &
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(1.0-cos(twopi*(/(i,i=0,nramp-1)/)/(2.0*nramp)))/2.0
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k1=(NSYM+1)*NSPS+1
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wave(k1:k1+nramp-1)=wave(k1:k1+nramp-1) * &
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(1.0+cos(twopi*(/(i,i=0,nramp-1)/)/(2.0*nramp)))/2.0
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wave(k1+nramp:NPTS)=0.0
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999 return
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end subroutine sfox_wave_gfsk
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