Transmit FT8 using a gaussian-filtered waveform.

This commit is contained in:
Joe Taylor 2019-02-22 13:39:39 -05:00
parent 574ad38400
commit 25bfa3798a
3 changed files with 35 additions and 11 deletions

View File

@ -66,7 +66,7 @@ program ft8sim_gfsk
n3=-1
call pack77(msg37,i3,n3,c77)
call genft8(msg37,i3,n3,msgsent37,msgbits,itone)
call gen_ft8wave(itone,NN,NSPS,fs,f0,cwave,NWAVE)
call gen_ft8wave(itone,NN,NSPS,fs,f0,cwave,xjunk,1,NWAVE) !Generate complex cwave
write(*,*)
write(*,'(a23,a37,3x,a7,i1,a1,i1)') 'New Style FT8 Message: ',msgsent37,'i3.n3: ',i3,'.',n3

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@ -1,4 +1,4 @@
subroutine gen_ft8wave(itone,nsym,nsps,fsample,f0,cwave,nwave)
subroutine gen_ft8wave(itone,nsym,nsps,fsample,f0,cwave,wave,icmplx,nwave)
!
! generate ft8 waveform using Gaussian-filtered frequency pulses.
!
@ -6,7 +6,7 @@ subroutine gen_ft8wave(itone,nsym,nsps,fsample,f0,cwave,nwave)
parameter(MAX_SECONDS=20)
real wave(nwave)
complex cwave(nwave)
real pulse(5760)
real pulse(23040)
real dphi(0:(nsym+2)*nsps-1)
integer itone(nsym)
logical first
@ -43,17 +43,28 @@ subroutine gen_ft8wave(itone,nsym,nsps,fsample,f0,cwave,nwave)
k=0
do j=0,nwave-1
k=k+1
wave(k)=sin(phi)
cwave(k)=cmplx(cos(phi),sin(phi))
if(icmplx.eq.0) then
wave(k)=sin(phi)
else
cwave(k)=cmplx(cos(phi),sin(phi))
endif
phi=mod(phi+dphi(j),twopi)
enddo
! Compute the ramp-up and ramp-down symbols
cwave(1:nsps)=cwave(1:nsps) * &
(1.0-cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
k1=(nsym+1)*nsps+1
cwave(k1:k1+nsps-1)=cwave(k1:k1+nsps-1) * &
(1.0+cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
if(icmplx.eq.0) then
wave(1:nsps)=wave(1:nsps) * &
(1.0-cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
k1=(nsym+1)*nsps+1
wave(k1:k1+nsps-1)=wave(k1:k1+nsps-1) * &
(1.0+cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
else
cwave(1:nsps)=cwave(1:nsps) * &
(1.0-cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
k1=(nsym+1)*nsps+1
cwave(k1:k1+nsps-1)=cwave(k1:k1+nsps-1) * &
(1.0+cos(twopi*(/(i,i=0,nsps-1)/)/(2.0*nsps)))/2.0
endif
return
end subroutine gen_ft8wave

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@ -102,6 +102,9 @@ extern "C" {
void genft4_(char* msg, int* ichk, char* msgsent, int itone[],
fortran_charlen_t, fortran_charlen_t);
void gen_ft8wave_(int itone[], int* nsym, int* nsps, float* fsample, float* f0,
float xjunk[], float wave[], int* icmplx, int* nwave);
void gen_ft4wave_(int itone[], int* nsym, int* nsps, float* fsample, float* f0,
float wave[], int* nwave);
@ -6861,7 +6864,17 @@ void MainWindow::transmit (double snr)
}
if (m_modeTx == "FT8") {
toneSpacing=12000.0/1920.0;
// toneSpacing=12000.0/1920.0;
toneSpacing=-3;
int nsym=79;
int nsps=4*1920;
float fsample=48000.0;
float f0=ui->TxFreqSpinBox->value() - m_XIT;
int icmplx=0;
int nwave=(nsym+2)*nsps;
gen_ft8wave_(const_cast<int *>(itone),&nsym,&nsps,&fsample,&f0,foxcom_.wave,
foxcom_.wave,&icmplx,&nwave);
if(m_config.x2ToneSpacing()) toneSpacing=2*12000.0/1920.0;
if(m_config.x4ToneSpacing()) toneSpacing=4*12000.0/1920.0;
if(SpecOp::FOX==m_config.special_op_id() and !m_tune) toneSpacing=-1;