mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2025-10-30 20:40:28 -04:00
587 lines
17 KiB
Fortran
587 lines
17 KiB
Fortran
program wsprcpmd
|
|
|
|
! Decode WSPRCPM data read from *.c2 or *.wav files.
|
|
|
|
! WSPRCPM is a WSPR-like mode based on full-response CPM.
|
|
!
|
|
! Currently configured to use (204,68) r=1/3 LDPC code, regular column weight 3.
|
|
! 50 data bits + 14 bit CRC + 4 "0" bits. The 4 "0" bits are unused bits that
|
|
! are not transmitted. At the decoder, these bits are treated as "AP" bits.
|
|
! This shortens the code to (200,64) r=0.32, slightly decreasing the code rate.
|
|
!
|
|
! Frame format is:
|
|
! d100 p32 d100 (232) channel symbols
|
|
!
|
|
use crc
|
|
include 'wsprcpm_params.f90'
|
|
parameter(NMAX=120*12000)
|
|
character arg*8,message*22,cbits*50,infile*80,fname*16,datetime*11
|
|
character ch1*1,ch4*4,cseq*31
|
|
character*22 decodes(100)
|
|
character*120 data_dir
|
|
character*32 uwbits
|
|
character*68 dmsg
|
|
complex c2(0:120*12000/32-1) !Complex waveform
|
|
complex cframe(0:216*200-1) !Complex waveform
|
|
complex cd(0:216*10-1) !Complex waveform
|
|
complex c1(0:9,0:1),c0(0:9,0:1)
|
|
complex ccor(0:1,216)
|
|
complex cp(0:1,0:1)
|
|
complex csum,cterm
|
|
real*8 fMHz
|
|
real rxdata(ND),llr(204) !Soft symbols
|
|
real sbits(216),sbits1(216),sbits3(216)
|
|
real ps(0:8191),psbest(0:8191)
|
|
real candidates(100,2)
|
|
integer iuniqueword0
|
|
integer isync(200) !Unique word
|
|
integer isync2(216)
|
|
! integer ipreamble(16) !Preamble vector
|
|
integer isyncword(16)
|
|
integer ihdr(11)
|
|
integer*2 iwave(NMAX) !Generated full-length waveform
|
|
integer*1,target :: idat(9)
|
|
integer*1 decoded(68),apmask(204),cw(204)
|
|
integer*1 hbits(216),hbits1(216),hbits3(216)
|
|
! data ipreamble/1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1/
|
|
data isyncword/0,1,3,2,1,0,2,3,2,3,1,0,3,2,0,1/
|
|
data cseq /'9D9F C48B 797A DD60 58CB 2EBC 6'/
|
|
data iuniqueword0/z'30C9E8AD'/
|
|
|
|
k=0
|
|
do i=1,31
|
|
ch1=cseq(i:i)
|
|
if(ch1.eq.' ') cycle
|
|
read(ch1,'(z1)') n
|
|
write(ch4,'(b4.4)') n
|
|
do j=1,4
|
|
k=k+1
|
|
isync(k)=0
|
|
if(ch4(j:j).eq.'1') isync(k)=1
|
|
enddo
|
|
enddo
|
|
isync(101:200)=isync(1:100)
|
|
|
|
fs=12000.0/NDOWN !Sample rate
|
|
dt=1.0/fs !Sample interval (s)
|
|
tt=NSPS*dt !Duration of "itone" symbols (s)
|
|
baud=1.0/tt !Keying rate for "itone" symbols (baud)
|
|
txt=NZ*dt !Transmission length (s)
|
|
h=0.50 !h=0.8 seems to be optimum for AWGN sensitivity (not for fading)
|
|
twopi=8.0*atan(1.0)
|
|
pi=4.0*atan(1.0)
|
|
|
|
nargs=iargc()
|
|
if(nargs.lt.1) then
|
|
print*,'Usage: wsprcpmd [-a <data_dir>] [-f fMHz] [-c ncoh] [-h h] file1 [file2 ...]'
|
|
go to 999
|
|
endif
|
|
iarg=1
|
|
data_dir="."
|
|
call getarg(iarg,arg)
|
|
if(arg(1:2).eq.'-a') then
|
|
call getarg(iarg+1,data_dir)
|
|
iarg=iarg+2
|
|
endif
|
|
call getarg(iarg,arg)
|
|
if(arg(1:2).eq.'-f') then
|
|
call getarg(iarg+1,arg)
|
|
read(arg,*) fMHz
|
|
iarg=iarg+2
|
|
endif
|
|
ncoh=1
|
|
if(arg(1:2).eq.'-h') then
|
|
call getarg(iarg+1,arg)
|
|
read(arg,*) h
|
|
iarg=iarg+2
|
|
endif
|
|
|
|
isync2(1:100)=isync(1:100)
|
|
isync2(101:116)=(/0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1/)
|
|
isync2(117:216)=isync(101:200)
|
|
|
|
! data MSB
|
|
! data sync tone
|
|
! 0 0 0
|
|
! 0 1 1
|
|
! 1 0 2
|
|
! 1 1 3
|
|
|
|
dphi=twopi*baud*(h/2.0)*dt*20 ! dt*10 is samp interval after downsample
|
|
do j=0,1
|
|
if(j.eq.0) then
|
|
dphi0=-3*dphi
|
|
dphi1=+1*dphi
|
|
else
|
|
dphi0=-1*dphi
|
|
dphi1=+3*dphi
|
|
endif
|
|
phi0=0.0
|
|
phi1=0.0
|
|
do i=0,9
|
|
c1(i,j)=cmplx(cos(phi1),sin(phi1))
|
|
c0(i,j)=cmplx(cos(phi0),sin(phi0))
|
|
phi1=mod(phi1+dphi1,twopi)
|
|
phi0=mod(phi0+dphi0,twopi)
|
|
enddo
|
|
cp(1,j)=cmplx(cos(phi1),sin(phi1))
|
|
cp(0,j)=cmplx(cos(phi0),sin(phi0))
|
|
enddo
|
|
|
|
open(13,file=trim(data_dir)//'/ALL_WSPR.TXT',status='unknown', &
|
|
position='append')
|
|
|
|
xs1=0.0
|
|
xs2=0.0
|
|
fr1=0.0
|
|
fr2=0.0
|
|
nav=0
|
|
ngood=0
|
|
|
|
do ifile=iarg,nargs
|
|
call getarg(ifile,infile)
|
|
open(10,file=infile,status='old',access='stream')
|
|
j1=index(infile,'.c2')
|
|
j2=index(infile,'.wav')
|
|
if(j1.gt.0) then
|
|
read(10,end=999) fname,ntrmin,fMHz,c2
|
|
read(fname(8:11),*) nutc
|
|
write(datetime,'(i11)') nutc
|
|
else if(j2.gt.0) then
|
|
read(10,end=999) ihdr,iwave
|
|
read(infile(j2-4:j2-1),*) nutc
|
|
datetime=infile(j2-11:j2-1)
|
|
call wsprcpm_downsample(iwave,c2)
|
|
else
|
|
print*,'Wrong file format?'
|
|
go to 999
|
|
endif
|
|
close(10)
|
|
|
|
fa=-100.0
|
|
fb=100.0
|
|
fs=12000.0/32.0
|
|
npts=120*12000.0/32.0
|
|
nsync=16
|
|
call getcandidate2(c2,npts,fs,fa,fb,ncand,candidates) !First approx for freq
|
|
ndecodes=0
|
|
do icand=1,ncand
|
|
fc0=candidates(icand,1)
|
|
xsnr=candidates(icand,2)
|
|
xmax=-1e32
|
|
do i=-7,7
|
|
ft=fc0+i*0.2
|
|
call noncoherent_frame_sync(c2,h,ft,isync2,is,xf1)
|
|
if(xf1.gt.xmax) then
|
|
xmax=xf1
|
|
fc1=ft
|
|
is0=is
|
|
endif
|
|
enddo
|
|
fcest=fc1
|
|
imode=0 ! refine freq
|
|
call coherent_sync(c2,h,isyncword,nsync,NSPS,is0,fcest,imode,xp0)
|
|
imode=1 ! refine istart
|
|
istart=is0
|
|
call coherent_sync(c2,h,isyncword,nsync,NSPS,istart,fcest,imode,xp1)
|
|
write(*,'(i5,i5,i5,6(f11.5,2x))') ifile-2,is0,istart,fc0,fc1,fcest,xf1,xp0,xp1
|
|
|
|
!genie sync
|
|
!istart=375
|
|
!fcest=0.0
|
|
do ijitter=0,4
|
|
io=-10*(ijitter/2+1)
|
|
if(mod(ijitter,2).eq.0) io=10*(ijitter/2)
|
|
ib=max(0,istart+io)
|
|
cframe=c2(ib:ib+216*200-1)
|
|
call downsample2(cframe,fcest,h,cd)
|
|
|
|
s2=sum(cd*conjg(cd))/(10*216)
|
|
cd=cd/sqrt(s2)
|
|
|
|
do nseq=1,5
|
|
if( nseq.eq.1 ) then ! noncoherent single-symbol detection
|
|
sbits1=0.0
|
|
do ibit=1,216
|
|
j=isync2(ibit)
|
|
ib=(ibit-1)*10
|
|
ccor(1,ibit)=sum(cd(ib:ib+9)*conjg(c1(0:9,j)))
|
|
ccor(0,ibit)=sum(cd(ib:ib+9)*conjg(c0(0:9,j)))
|
|
sbits1(ibit)=abs(ccor(1,ibit))-abs(ccor(0,ibit))
|
|
hbits1(ibit)=0
|
|
if(sbits1(ibit).gt.0) hbits1(ibit)=1
|
|
enddo
|
|
sbits=sbits1
|
|
hbits=hbits1
|
|
sbits3=sbits1
|
|
hbits3=hbits1
|
|
elseif( nseq.ge.2 ) then
|
|
ps=0
|
|
if( nseq.eq. 2 ) nbit=3
|
|
if( nseq.eq. 3 ) nbit=5
|
|
if( nseq.eq. 4 ) nbit=7
|
|
if( nseq.eq. 5 ) nbit=9
|
|
if( nseq.eq. 6 ) nbit=11
|
|
if( nseq.eq. 7 ) nbit=13
|
|
numseq=2**(nbit)
|
|
do ibit=nbit/2+1,216-nbit/2
|
|
ps=0.0
|
|
pmax=0.0
|
|
do iseq=0,numseq-1
|
|
csum=0.0
|
|
cterm=1.0
|
|
k=1
|
|
do i=nbit-1,0,-1
|
|
j=isync2(ibit-(nbit/2+1)+k)
|
|
ibb=iand(iseq/(2**i),1)
|
|
csum=csum+ccor(ibb,ibit-(nbit/2+1)+k)*cterm
|
|
cterm=cterm*conjg(cp(ibb,j))
|
|
k=k+1
|
|
enddo
|
|
ps(iseq)=abs(csum)
|
|
if( ps(iseq) .gt. pmax ) then
|
|
pmax=ps(iseq)
|
|
ibflag=1
|
|
endif
|
|
enddo
|
|
if( ibflag .eq. 1 ) then
|
|
psbest=ps
|
|
ibflag=0
|
|
endif
|
|
call getmetric2(2**(nbit/2),psbest,numseq,sbits3(ibit))
|
|
hbits3(ibit)=0
|
|
if(sbits3(ibit).gt.0) hbits3(ibit)=1
|
|
enddo
|
|
sbits=sbits3
|
|
hbits=hbits3
|
|
endif
|
|
|
|
rxdata(1:100)=sbits(1:100)
|
|
rxdata(101:200)=sbits(117:216);
|
|
rxav=sum(rxdata(1:200))/200.0
|
|
rx2av=sum(rxdata(1:200)*rxdata(1:200))/200.0
|
|
rxsig=sqrt(rx2av-rxav*rxav)
|
|
rxdata=rxdata/rxsig
|
|
sigma=0.90
|
|
llr(201:204)=-5.0
|
|
llr(1:200)=2*rxdata/(sigma*sigma)
|
|
apmask=0
|
|
apmask(201:204)=1
|
|
max_iterations=40
|
|
ifer=0
|
|
call bpdecode204(llr,apmask,max_iterations,decoded,cw,nharderror,niterations)
|
|
nhardmin=-1
|
|
if(nharderror.lt.0) call osd204(llr,apmask,4,decoded,cw,nhardmin,dmin)
|
|
if(sum(decoded).eq.0) cycle
|
|
if(nhardmin.ge.0 .or. nharderror.ge.0) then
|
|
idat=0
|
|
write(dmsg,'(68i1)') decoded
|
|
read(dmsg(1:50),'(6b8.8,b2.2)') idat(1:7)
|
|
idat(7)=idat(7)*64
|
|
read(dmsg(51:64),'(b14.14)') ndec_crc
|
|
ncalc_crc=iand(crc14(c_loc(idat),9),z'FFFF')
|
|
nbadcrc=1
|
|
if(ncalc_crc .eq. ndec_crc) nbadcrc=0
|
|
else
|
|
cycle
|
|
endif
|
|
if( nbadcrc.eq.0 ) then
|
|
write(cbits,1200) decoded(1:50)
|
|
1200 format(50i1)
|
|
read(cbits,1202) idat
|
|
1202 format(8b8,b4)
|
|
idat(7)=ishft(idat(7),6)
|
|
call wqdecode(idat,message,itype)
|
|
idupe=0
|
|
do i=1,ndecodes
|
|
if(decodes(i).eq.message) idupe=1
|
|
enddo
|
|
if(idupe.eq.1) goto 888
|
|
ndecodes=ndecodes+1
|
|
decodes(ndecodes)=message
|
|
nsnr=nint(xsnr)
|
|
freq=fMHz + 1.d-6*(fc1+fbest)
|
|
nfdot=0
|
|
write(13,1210) datetime,0,nsnr,xdt,freq,message,nfdot
|
|
1210 format(a11,2i4,f6.2,f12.7,2x,a22,i3)
|
|
write(*,1212) datetime(8:11),nsnr,xdt,freq,nfdot,message,'*',nseq,ijitter,nharderror,nhardmin
|
|
1212 format(a4,i4,f5.1,f11.6,i3,2x,a22,a1,i5,i5,i5,i5)
|
|
goto 888
|
|
endif
|
|
enddo ! nseq
|
|
enddo !jitter
|
|
888 continue
|
|
enddo !candidate list
|
|
enddo !files
|
|
|
|
write(*,1120)
|
|
1120 format("<DecodeFinished>")
|
|
|
|
999 end program wsprcpmd
|
|
|
|
|
|
subroutine coherent_sync(c2,h,isyncword,nsync,nsps,istart,fc,imode,xmax)
|
|
! imode=0: refine fc using given istart
|
|
! imode=1: refine istart using given fc
|
|
complex c2(0:120*12000/32-1)
|
|
complex csync(0:16*200-1)
|
|
complex ctmp1(0:4*16*200-1)
|
|
complex ctwkp(0:16*200-1)
|
|
complex ccohp(0:15)
|
|
integer isyncword(nsync)
|
|
logical first/.true./
|
|
save dt,first,twopi,csync
|
|
|
|
if(first) then
|
|
baud=12000.0/6400.0
|
|
dt=32.0/12000.0
|
|
twopi=8.0*atan(1.0)
|
|
k=0
|
|
phi=0.0
|
|
dphi=twopi*baud*0.5*h*dt
|
|
do i=1,16
|
|
dp=dphi*2*(isyncword(i)-1.5)
|
|
do j=1,200
|
|
csync(k)=cmplx(cos(phi),sin(phi))
|
|
phi=mod(phi+dp,twopi)
|
|
k=k+1
|
|
enddo
|
|
enddo
|
|
first=.false.
|
|
endif
|
|
dphi=twopi*fc*dt
|
|
ctwkp=cmplx(0.0,0.0)
|
|
phi=0
|
|
do i=0,nsync*nsps-1
|
|
ctwkp(i)=csync(i)*cmplx(cos(phi),sin(phi))
|
|
phi=mod(phi+dphi,twopi)
|
|
enddo
|
|
ipstart=istart+100*200
|
|
ctmp1=0.0
|
|
xmax=0.0
|
|
if(imode.eq.1) then !refine DT with given fc
|
|
do iii=-50,50,5
|
|
ctmp1(0:16*200-1)=c2(ipstart+iii:ipstart+iii+16*200-1)*conjg(ctwkp)
|
|
xnorm=sqrt(sum(abs(ctmp1(0:16*200-1))**2))*sqrt(16.0*200.0)
|
|
xc=abs(sum(ctmp1))/xnorm
|
|
if(xc.gt.xmax) then
|
|
iiibest=iii
|
|
xmax=xc
|
|
endif
|
|
enddo
|
|
istart=istart+iiibest
|
|
return
|
|
endif
|
|
! else refine fc with given DT
|
|
ctmp1(0:16*200-1)=c2(ipstart:ipstart+16*200-1)*conjg(ctwkp)
|
|
xnorm=sqrt(sum(abs(ctmp1(0:16*200-1))**2))*sqrt(16.0*200.0)
|
|
ctmp1=ctmp1/xnorm
|
|
call four2a(ctmp1,4*16*200,1,-1,1) !c2c FFT to freq domain
|
|
xmax=0.0
|
|
ctmp1=cshift(ctmp1,-200)
|
|
dfp=1/(4*6400.0/12000.0*16)
|
|
! do i=150,250
|
|
do i=190,210
|
|
xa=abs(ctmp1(i))
|
|
!write(51,*) (i-200)*dfp,xa
|
|
if(xa.gt.xmax) then
|
|
ishift=i
|
|
xmax=xa
|
|
endif
|
|
enddo
|
|
delta=(ishift-200)*dfp
|
|
xm1=abs(ctmp1(ishift-1))
|
|
x0=abs(ctmp1(ishift))
|
|
xp1=abs(ctmp1(ishift+1))
|
|
xint=(log(xm1)-log(xp1))/(log(xm1)+log(xp1)-2*log(x0))
|
|
delta2=delta+xint*dfp/2.0
|
|
fc=fc+delta2
|
|
return
|
|
end subroutine coherent_sync
|
|
|
|
subroutine noncoherent_frame_sync(c2,h,fc,isync2,istart,ssmax)
|
|
complex c2(0:120*12000/32-1)
|
|
complex ct0(0:199),ct1(0:199),ct2(0:199),ct3(0:199)
|
|
integer isync2(216)
|
|
|
|
twopi=8.0*atan(1.0)
|
|
dt=32.0/12000.0
|
|
baud=12000.0/6400.0
|
|
imax=370 ! defines dt search range (375 samples/s)
|
|
ssmax=-1e32
|
|
izero=375
|
|
do it = -imax,imax,5
|
|
! noncoherent wspr-type dt estimation
|
|
dp0=twopi*(fc-1.5*h*baud)*dt
|
|
dp1=twopi*(fc-0.5*h*baud)*dt
|
|
dp2=twopi*(fc+0.5*h*baud)*dt
|
|
dp3=twopi*(fc+1.5*h*baud)*dt
|
|
th0=0.0
|
|
th1=0.0
|
|
th2=0.0
|
|
th3=0.0
|
|
do i=0,199
|
|
ct0(i)=cmplx(cos(th0),sin(th0))
|
|
ct1(i)=cmplx(cos(th1),sin(th1))
|
|
ct2(i)=cmplx(cos(th2),sin(th2))
|
|
ct3(i)=cmplx(cos(th3),sin(th3))
|
|
th0=mod(th0+dp0,twopi)
|
|
th1=mod(th1+dp1,twopi)
|
|
th2=mod(th2+dp2,twopi)
|
|
th3=mod(th3+dp3,twopi)
|
|
enddo
|
|
xs=0.0
|
|
xn=0.0
|
|
do is=1,216
|
|
i0=izero+it+(is-1)*200
|
|
p0=abs(sum(c2(i0:i0+199)*conjg(ct0)))
|
|
p1=abs(sum(c2(i0:i0+199)*conjg(ct1)))
|
|
p2=abs(sum(c2(i0:i0+199)*conjg(ct2)))
|
|
p3=abs(sum(c2(i0:i0+199)*conjg(ct3)))
|
|
p0=p0**2
|
|
p1=p1**2
|
|
p2=p2**2
|
|
p3=p3**2
|
|
if(isync2(is).eq.0) then
|
|
! xs=xs+(p0+p2)/2.0
|
|
xs=xs+max(p0,p2)
|
|
xn=xn+(p1+p3)/2.0
|
|
elseif(isync2(is).eq.1) then
|
|
! xs=xs+(p1+p3)/2.0
|
|
xs=xs+max(p1,p3)
|
|
xn=xn+(p0+p2)/2.0
|
|
endif
|
|
enddo
|
|
sy=xs/xn
|
|
!write(41,*) it,sy
|
|
if(sy.gt.ssmax) then
|
|
ioffset=it
|
|
ssmax=sy
|
|
endif
|
|
enddo
|
|
istart=izero+ioffset
|
|
return
|
|
end subroutine noncoherent_frame_sync
|
|
|
|
subroutine getmetric2(ib,ps,ns,xmet)
|
|
real ps(0:ns-1)
|
|
xm1=0
|
|
xm0=0
|
|
do i=0,ns-1
|
|
if( iand(i/ib,1) .eq. 1 .and. ps(i) .gt. xm1 ) xm1=ps(i)
|
|
if( iand(i/ib,1) .eq. 0 .and. ps(i) .gt. xm0 ) xm0=ps(i)
|
|
enddo
|
|
xmet=xm1-xm0
|
|
return
|
|
end subroutine getmetric2
|
|
|
|
subroutine downsample2(ci,f0,h,co)
|
|
parameter(NI=216*200,NH=NI/2,NO=NI/20) ! downsample from 200 samples per symbol to 10
|
|
complex ci(0:NI-1),ct(0:NI-1)
|
|
complex co(0:NO-1)
|
|
fs=12000.0/32.0
|
|
df=fs/NI
|
|
ct=ci
|
|
call four2a(ct,NI,1,-1,1) !c2c FFT to freq domain
|
|
i0=nint(f0/df)
|
|
ct=cshift(ct,i0)
|
|
co=0.0
|
|
co(0)=ct(0)
|
|
b=max(1.0,h)*8.0
|
|
do i=1,NO/2
|
|
arg=(i*df/b)**2
|
|
filt=exp(-arg)
|
|
co(i)=ct(i)*filt
|
|
co(NO-i)=ct(NI-i)*filt
|
|
enddo
|
|
co=co/NO
|
|
call four2a(co,NO,1,1,1) !c2c FFT back to time domain
|
|
return
|
|
end subroutine downsample2
|
|
|
|
subroutine getcandidate2(c,npts,fs,fa,fb,ncand,candidates)
|
|
parameter(NDAT=200,NFFT1=120*12000/32,NH1=NFFT1/2,NFFT2=120*12000/320,NH2=NFFT2/2)
|
|
complex c(0:npts-1) !Complex waveform
|
|
complex cc(0:NFFT1-1)
|
|
complex csfil(0:NFFT2-1)
|
|
complex cwork(0:NFFT2-1)
|
|
real bigspec(0:NFFT2-1)
|
|
complex c2(0:NFFT1-1) !Short spectra
|
|
real s(-NH1+1:NH1) !Coarse spectrum
|
|
real ss(-NH1+1:NH1) !Smoothed coarse spectrum
|
|
real candidates(100,2)
|
|
integer indx(NFFT2-1)
|
|
logical first
|
|
data first/.true./
|
|
save first,w,df,csfil
|
|
|
|
if(first) then
|
|
df=10*fs/NFFT1
|
|
csfil=cmplx(0.0,0.0)
|
|
do i=0,NFFT2-1
|
|
csfil(i)=exp(-((i-NH2)/32.0)**2) ! revisit this
|
|
enddo
|
|
csfil=cshift(csfil,NH2)
|
|
call four2a(csfil,NFFT2,1,-1,1)
|
|
first=.false.
|
|
endif
|
|
|
|
cc=cmplx(0.0,0.0)
|
|
cc(0:npts-1)=c;
|
|
call four2a(cc,NFFT1,1,-1,1)
|
|
cc=abs(cc)**2
|
|
call four2a(cc,NFFT1,1,-1,1)
|
|
cwork(0:NH2)=cc(0:NH2)*conjg(csfil(0:NH2))
|
|
cwork(NH2+1:NFFT2-1)=cc(NFFT1-NH2+1:NFFT1-1)*conjg(csfil(NH2+1:NFFT2-1))
|
|
|
|
call four2a(cwork,NFFT2,1,+1,1)
|
|
bigspec=cshift(real(cwork),-NH2)
|
|
il=NH2+fa/df
|
|
ih=NH2+fb/df
|
|
nnl=ih-il+1
|
|
call indexx(bigspec(il:il+nnl-1),nnl,indx)
|
|
xn=bigspec(il-1+indx(nint(0.3*nnl)))
|
|
bigspec=bigspec/xn
|
|
ncand=0
|
|
do i=il,ih
|
|
if((bigspec(i).gt.bigspec(i-1)).and. &
|
|
(bigspec(i).gt.bigspec(i+1)).and. &
|
|
(bigspec(i).gt.1.12).and.ncand.lt.100) then
|
|
ncand=ncand+1
|
|
candidates(ncand,1)=df*(i-NH2)
|
|
candidates(ncand,2)=10*log10(bigspec(i)-1)-26.0
|
|
endif
|
|
enddo
|
|
return
|
|
end subroutine getcandidate2
|
|
|
|
subroutine wsprcpm_downsample(iwave,c)
|
|
|
|
! Input: i*2 data in iwave() at sample rate 12000 Hz
|
|
! Output: Complex data in c(), sampled at 400 Hz
|
|
|
|
include 'wsprcpm_params.f90'
|
|
parameter (NMAX=120*12000,NFFT2=NMAX/32)
|
|
integer*2 iwave(NMAX)
|
|
complex c(0:NMAX/32-1)
|
|
complex c1(0:NFFT2-1)
|
|
complex cx(0:NMAX/2)
|
|
real x(NMAX)
|
|
equivalence (x,cx)
|
|
|
|
df=12000.0/NMAX
|
|
x=iwave
|
|
call four2a(x,NMAX,1,-1,0) !r2c FFT to freq domain
|
|
i0=nint(1500.0/df)
|
|
c1(0)=cx(i0)
|
|
do i=1,NFFT2/2
|
|
c1(i)=cx(i0+i)
|
|
c1(NFFT2-i)=cx(i0-i)
|
|
enddo
|
|
c1=c1/NFFT2
|
|
call four2a(c1,NFFT2,1,1,1) !c2c FFT back to time domain
|
|
c=c1(0:NMAX/32-1)
|
|
return
|
|
end subroutine wsprcpm_downsample
|
|
|