mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-09-17 10:46:33 -04:00
a9623703b3
changes on the C++ side. Basically works except that Tx audio has incorrect DT and audio is truncated at the end. Also, command line decoding using JT9 is not as sensitive as decoding from within WSJT-X.
67 lines
1.8 KiB
Fortran
67 lines
1.8 KiB
Fortran
subroutine gen_ft4wave(itone,nsym,nsps,fsample,f0,cwave,wave,icmplx,nwave)
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real wave(nwave)
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complex cwave(nwave)
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real pulse(6912) !576*4*3
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real dphi(0:250000-1)
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integer itone(nsym)
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logical first
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data first/.true./
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save pulse,first,twopi,dt,hmod
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if(first) then
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twopi=8.0*atan(1.0)
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dt=1.0/fsample
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hmod=1.0
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! Compute the smoothed frequency-deviation pulse
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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(1.0,tt)
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enddo
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first=.false.
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endif
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! Compute the smoothed frequency waveform.
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! Length = (nsym+2)*nsps samples, zero-padded
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dphi_peak=twopi*hmod/real(nsps)
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dphi=0.0
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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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! Calculate and insert the audio waveform
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phi=0.0
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dphi = dphi + twopi*f0*dt !Shift frequency up by f0
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wave=0.
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if(icmplx.eq.1) cwave=0.
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k=0
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do j=0,nwave-1
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k=k+1
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if(icmplx.eq.0) then
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wave(k)=sin(phi)
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else
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cwave(k)=cmplx(cos(phi),sin(phi))
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endif
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phi=mod(phi+dphi(j),twopi)
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enddo
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! Compute the ramp-up and ramp-down symbols
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if(icmplx.eq.0) then
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wave(1:nsps)=wave(1:nsps) * &
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(1.0-cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
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k1=(nsym+1)*nsps+1
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wave(k1:k1+nsps-1)=wave(k1:k1+nsps-1) * &
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(1.0+cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
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else
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cwave(1:nsps)=cwave(1:nsps) * &
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(1.0-cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
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k1=(nsym+1)*nsps+1
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cwave(k1:k1+nsps-1)=cwave(k1:k1+nsps-1) * &
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(1.0+cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
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endif
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return
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end subroutine gen_ft4wave
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