WSJT-X/lib/analytic.f90
2016-12-22 17:21:23 +00:00

83 lines
2.5 KiB
Fortran

subroutine analytic(d,npts,nfft,c,dpc,bseq,bdeq)
! Convert real data to analytic signal
parameter (NFFTMAX=1024*1024)
real d(npts) ! passband signal
real h(NFFTMAX/2) ! real BPF magnitude
real dpc(3),dpclast(3) ! dynamic phase coeffs
real spc(3),spclast(3) ! static phase coeffs
real ac(5) ! currently unused static amp coeffs
real fp
complex corrs(NFFTMAX/2) ! allpass static phase correction
complex corrd(NFFTMAX/2) ! allpass overall phase correction
complex c(NFFTMAX) ! analytic signal
logical*1 bseq ! boolean static equalizer flag
logical*1 bdeq ! boolean dynamic equalizer flag
logical*1 bseqlast
data nfft0/0/
data bseqlast/.false./
data spclast/0.0,0.0,0.0/
data spc/-0.952,0.768,-0.565/ ! baseline phase coeffs for TS2000
data ac/1.0,0.05532,0.11438,0.12918,0.09274/ ! amp coeffs for TS2000
save nfft0,h,spc,spclast,dpclast,ac,pi,t,beta
df=12000.0/nfft
nh=nfft/2
if( nfft.ne.nfft0 ) then
pi=4.0*atan(1.0)
t=1.0/2000.0
beta=0.1
do i=1,nh+1
ff=(i-1)*df
f=ff-1500.0
h(i)=1.0
if(abs(f).gt.(1-beta)/(2*t) .and. abs(f).le.(1+beta)/(2*t)) then
h(i)=h(i)*0.5*(1+cos((pi*t/beta )*(abs(f)-(1-beta)/(2*t))))
endif
enddo
nfft0=nfft
endif
if( any(spclast .ne. spc) .or. any(dpclast .ne. dpc) ) then
spclast=spc
dpclast=dpc
do i=1,nh+1
ff=(i-1)*df
f=ff-1500.0
fp=f/1000.0
ps=fp*fp*(spc(1)+fp*(spc(2)+fp*spc(3)))
corrs(i)=cmplx(cos(ps),sin(ps))
pd=fp*fp*(dpc(1)+fp*(dpc(2)+fp*dpc(3)))
corrd(i)=cmplx(cos(pd),sin(pd))
enddo
endif
fac=2.0/nfft
c(1:npts)=fac*d(1:npts)
c(npts+1:nfft)=0.
call four2a(c,nfft,1,-1,1) !Forward c2c FFT
if( (.not. bseq) .and. (.not. bdeq) ) then
c(1:nh+1)=h(1:nh+1)*c(1:nh+1)
else if( bseq .and. (.not. bdeq) ) then
c(1:nh+1)=h(1:nh+1)*corrs(1:nh+1)*c(1:nh+1)
else if( (.not. bseq) .and. bdeq ) then
c(1:nh+1)=h(1:nh+1)*corrd(1:nh+1)*c(1:nh+1)
else if( bseq .and. bdeq ) then
c(1:nh+1)=h(1:nh+1)*corrs(1:nh+1)*corrd(1:nh+1)*c(1:nh+1)
endif
c(1)=0.5*c(1) !Half of DC term
c(nh+2:nfft)=0. !Zero the negative frequencies
call four2a(c,nfft,1,1,1) !Inverse c2c FFT
spclast=spc
dpclast=dpc
return
end subroutine analytic