Update wsprcpm simulator and decoder.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8603 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke 2018-04-03 14:55:55 +00:00
parent 396aab7274
commit 1f9d73963b
5 changed files with 286 additions and 333 deletions

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@ -15,20 +15,23 @@ subroutine genwsprcpm(msg,msgsent,itone)
integer icw(ND)
integer id(NS+ND)
integer jd(NS+ND)
integer ipreamble(32) !Long sync vector
integer isync(32) !Long sync vector
integer ipreamble(16) !Freq estimation preamble
integer isync(200) !Long sync vector
integer itone(NN)
integer*8 n8
data ipreamble/1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1/
data ipreamble/1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1/
data first/.true./
data iuniqueword0/z'30C9E8AD'/
save first,isync,ipreamble
if(first) then
write(sbits,'(b32.32)') iuniqueword0
read(sbits,'(32i1)') isync
ipreamble=2*ipreamble-1
isync=2*isync-1
read(sbits,'(32i1)') isync(1:32)
read(sbits,'(32i1)') isync(33:64)
read(sbits,'(32i1)') isync(65:96)
read(sbits,'(32i1)') isync(97:128)
read(sbits,'(32i1)') isync(129:160)
read(sbits,'(32i1)') isync(161:192)
read(sbits,'(8i1)') isync(193:200)
first=.false.
endif
@ -52,17 +55,16 @@ write(*,'(a6,b16.16)') 'icrc: ',icrc
write(*,'(50i1,1x,14i1,1x,4i1)') msgbits
call encode204(msgbits,codeword) !Encode the test message
icw=2*codeword - 1 !NRZ codeword
! Message structure:
! s32 d200 p32
itone(1:32)=isync
itone(33:232)=icw
itone(233:264)=ipreamble
! do i=1,264
! write(*,*) i,itone(i)
! enddo
! d100 p16 d100
itone(1:100)=isync(1:100)+2*codeword(1:100)
itone(101:116)=ipreamble+1
itone(117:216)=isync(101:200)+2*codeword(101:200)
itone=2*itone-3
do i=1,216
write(*,*) i,itone(i)
enddo
return
end subroutine genwsprcpm

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@ -1,11 +1,11 @@
parameter (KK=64) !Information bits (50 + CRC14) ?
parameter (ND=200) !Data symbols: LDPC (204,68), r=1/3, don't send last 4 bits
parameter (NS=64) !Sync symbols (2x32)
parameter (NN=NS+ND) !Total symbols (264)
parameter (NS=16) !Sync symbols (16)
parameter (NN=NS+ND) !Total symbols (216)
parameter (NSPS0=5300) !Samples per symbol at 12000 S/s
parameter (NSPS0=6400) !Samples per symbol at 12000 S/s
parameter (NDOWN=53) !Downsample to 100 samples per symbol...
parameter (NDOWN=32) !Downsample to 200 sa/symbol (375 Hz) for candidate selection
parameter (NSPS=NSPS0/NDOWN) !Samples per symbol
parameter (NZ=NSPS*NN) !Samples in baseband waveform

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@ -1,4 +1,4 @@
subroutine wsprcpm_wav(baud,xdt,h1,h2,f0,itone,snrdb,iwave)
subroutine wsprcpm_wav(baud,xdt,h,f0,itone,snrdb,iwave)
! Generate iwave() from itone().
@ -23,23 +23,10 @@ subroutine wsprcpm_wav(baud,xdt,h1,h2,f0,itone,snrdb,iwave)
sig=1.0
endif
dphi01=twopi*(f0-(h1/2.0d0)*baud)*dt
dphi11=twopi*(f0+(h1/2.0d0)*baud)*dt
dphi02=twopi*(f0-(h2/2.0d0)*baud)*dt
dphi12=twopi*(f0+(h2/2.0d0)*baud)*dt
phi=0.d0
k=nint(xdt/dt)
do j=1,NN
if( mod(j,2).eq.0 ) then
dphi0=dphi01
dphi1=dphi11
else
dphi0=dphi02
dphi1=dphi12
endif
dphi=dphi0
if(itone(j).eq.1) dphi=dphi1
if(k.eq.0) phi=-dphi
dphi=twopi*(f0+itone(j)*(h/2.0d0)*baud)*dt
do i=1,NSPS0
k=k+1
phi=phi+dphi

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@ -4,136 +4,89 @@ program wsprcpmd
! WSPRCPM is a WSPR-like mode based on full-response CPM.
!
! Modulation Capabilities include:
! support for multi-h cpm with two modulation indexes: [h1,h2].
! h1,h2 (modulation index) are variable; h1=h2=0.5 is MSK, h1=h2=1.0 is standard
! fsk intended for noncoherent demodulation.
! demodulator uses noncoherent sequence detection with variable window size.
! symbol demodulation is done symbol-by-symbol - each symbol is
! estimated using a data frame comprising N symbol intervals, where N can
! be 1, 3, 5, 7, 9, 11. The central symbol is estimated and then the window
! is stepped forward by one symbol.
! soft symbols are decoded by log-domain belief propagation followed by ordered-
! statistics decoding.
!
! 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:
! s32 d200 p32 (264) channel symbols
! 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*22 decodes(100)
character*120 data_dir
character*32 uwbits
character*68 dmsg
complex csync(0:32*100-1) !Sync symbols only, from cbb
complex cpreamble(0:32*100-1) !Sync symbols only, from cbb
complex cp2(0:32*100-1)
complex ctwks(0:32*100-1)
complex ctwkp(0:32*100-1)
complex c2(0:120*12000/53-1) !Complex waveform
complex ctmp(0:4*32*100-1)
complex cframe(0:264*100-1) !Complex waveform
complex cd(0:264*100-1) !Complex waveform
complex c1(0:9,1:2),c0(0:9,1:2)
complex ccor(0:1,264)
complex csum,cp(0:1,1:2),cterm
complex ccohs(0:31)
complex ccohp(0:31)
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 csum,cterm
real*8 fMHz
real rxdata(ND),llr(204) !Soft symbols
real sbits(264),sbits1(264),sbits3(264)
real sbits(216),sbits1(216),sbits3(216)
real ps(0:8191),psbest(0:8191)
real candidates(100,2)
integer iuniqueword0
integer isync(32) !Unique word
integer ipreamble(32) !Preamble vector
integer isync(200) !Unique word
integer isync2(216)
integer ipreamble(16) !Preamble vector
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(264),hbits1(264),hbits3(264)
data ipreamble/1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1/
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 iuniqueword0/z'30C9E8AD'/
write(uwbits,'(b32.32)') iuniqueword0
read(uwbits,'(32i1)') isync
ipreamble=2*ipreamble-1
isync=2*isync-1
read(uwbits,'(32i1)') isync(1:32)
read(uwbits,'(32i1)') isync(33:64)
read(uwbits,'(32i1)') isync(65:96)
read(uwbits,'(32i1)') isync(97:128)
read(uwbits,'(32i1)') isync(129:160)
read(uwbits,'(32i1)') isync(161:192)
read(uwbits,'(8i1)') isync(193:200)
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)
h1=0.80 !h=0.8 seems to be optimum for AWGN sensitivity (not for fading)
h2=0.80
h=1.00 !h=0.8 seems to be optimum for AWGN sensitivity (not for fading)
twopi=8.0*atan(1.0)
dphi11=twopi*baud*(h1/2.0)*dt
dphi01=-twopi*baud*(h1/2.0)*dt
dphi12=twopi*baud*(h2/2.0)*dt
dphi02=-twopi*baud*(h2/2.0)*dt
k=0
phi=0.0
do i=1,32
if( mod(i,2) .eq. 0 ) then
dphi1=dphi11
dphi0=dphi01
else
dphi1=dphi12
dphi0=dphi02
endif
dphi=dphi0
if( isync(i) .eq. 1 ) dphi=dphi1
do j=1,100
phi=mod(phi+dphi,twopi)
csync(k)=cmplx(cos(phi),sin(phi))
k=k+1
enddo
enddo
k=0
phi=0.0
do i=1,32
if( mod(i,2) .eq. 0 ) then
dphi1=dphi11
dphi0=dphi01
else
dphi1=dphi12
dphi0=dphi02
endif
dphi=dphi0
if( ipreamble(i) .eq. 1 ) dphi=dphi1
do j=1,100
phi=mod(phi+dphi,twopi)
cpreamble(k)=cmplx(cos(phi),sin(phi))
k=k+1
enddo
enddo
isync2(1:100)=isync(1:100)
isync2(101:104)=0 ! This is *not* backwards.
isync2(105:112)=1
isync2(113:116)=0
isync2(117:216)=isync(101:200)
dphi1=twopi*baud*(h1/2.0)*dt*10 ! dt*10 is samp interval after downsample
dphi2=twopi*baud*(h2/2.0)*dt*10 ! dt*10 is samp interval after downsample
cp(1,1)=cmplx(cos(dphi1*10),sin(dphi1*10))
cp(0,1)=conjg(cp(1,1))
cp(1,2)=cmplx(cos(dphi2*10),sin(dphi2*10))
cp(0,2)=conjg(cp(1,2))
do j=1,2
if( j.eq.1 ) then
dphi=dphi1
! 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
dphi=dphi2
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+dphi,twopi)
phi0=mod(phi0-dphi,twopi)
phi1=mod(phi1+dphi1,twopi)
phi0=mod(phi0+dphi0,twopi)
enddo
enddo
@ -156,14 +109,14 @@ program wsprcpmd
iarg=iarg+2
endif
ncoh=1
npdi=32
npdi=16
if(arg(1:2).eq.'-c') then
call getarg(iarg+1,arg)
read(arg,*) ncoh
iarg=iarg+2
npdi=32/ncoh
npdi=16/ncoh
endif
write(*,*) 'ncoh: ',ncoh,' npdi: ',npdi
! write(*,*) 'ncoh: ',ncoh,' npdi: ',npdi
open(13,file=trim(data_dir)//'/ALL_WSPR.TXT',status='unknown', &
position='append')
@ -197,123 +150,43 @@ program wsprcpmd
fa=-100.0
fb=100.0
fs=12000.0/53.0
npts=120*12000/53
nsync=32
call getcandidate2(c2,npts,fs,fa,fb,fc1,xsnr) !First approx for freq
fcest=fc1
do iii=1,2
izero=226
dphi=twopi*fcest*dt
ctwks=cmplx(0.0,0.0)
ctwkp=cmplx(0.0,0.0)
phi=0
do i=0,nsync*NSPS-1
phi=mod(phi+dphi,twopi)
ctwks(i)=csync(i)*cmplx(cos(phi),sin(phi))
ctwkp(i)=cpreamble(i)*cmplx(cos(phi),sin(phi))
enddo
imax=100
xcmax=-1e32
do it = -imax,imax
its=izero+it
ccohs=0.0
do k=0,npdi-1
is=k*ncoh*nsps
ccohs(k)=sum(c2(its+is:its+is+ncoh*nsps-1)*conjg(ctwks(is:is+ncoh*nsps-1)))
ccohs(k)=ccohs(k)/(ncoh*nsps)
enddo
! term1=sum(abs(ccohs(0:npdi-1))**2)
itp=izero+it+232*100
ccohp=0.0
do k=0,npdi-1
is=k*ncoh*nsps
ccohp(k)=sum(c2(itp+is:itp+is+ncoh*nsps-1)*conjg(ctwkp(is:is+ncoh*nsps-1)))
ccohp(k)=ccohp(k)/(ncoh*nsps)
enddo
csum=0.0
terms=0.0
do n=1,npdi-1
do k=n,npdi-1
csum=csum+ccohs(k)*conjg(ccohs(k-n))
enddo
terms=terms+abs(csum)
enddo
csum=0.0
termp=0.0
do n=1,npdi-1
do k=n,npdi-1
csum=csum+ccohp(k)*conjg(ccohp(k-n))
enddo
termp=termp+abs(csum)
enddo
!write(23,*) it,terms,termp
xmetric=sqrt(terms*termp)
if( xmetric .gt. xcmax ) then
xcmax=xmetric
ibestt=it
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=-5,5
ft=fc0+i*0.2
call noncoherent_frame_sync(c2,ft,isync2,is,xf1)
if(xf1.gt.xmax) then
xmax=xf1
fc1=ft
is0=is
endif
enddo
call coherent_preamble_fsync(c2,ipreamble,nsync,NSPS,is0,fc1,fcest,xp1)
call noncoherent_frame_sync(c2,fcest,isync2,istart,xf2)
write(*,'(i5,i5,i5,4(f11.5,2x))') ifile,iii,istart,fc0,fc1,fcest
istart=izero+ibestt
if(iii .eq. 2) goto 887
ctmp=0.0
ctmp(0:32*100-1)=c2(istart+232*100:istart+264*100-1)*conjg(ctwkp)
call four2a(ctmp,4*32*100,1,-1,1) !c2c FFT to freq domain
xmax=0.0
ctmp=cshift(ctmp,-200)
do i=150,250
xa=abs(ctmp(i))
if(xa.gt.xmax) then
ishift=i
xmax=xa
endif
enddo
dfp=1/(4*5300.0/12000.0*32)
delta=(ishift-200)*dfp
! need to add bounds protection
xm1=abs(ctmp(ishift-1))
x0=abs(ctmp(ishift))
xp1=abs(ctmp(ishift+1))
xint=(log(xm1)-log(xp1))/(log(xm1)+log(xp1)-2*log(x0))
delta2=delta+xint*dfp/2.0
fcest=fcest+delta2
enddo
887 write(*,'(i4,i5,5(2x,f9.5))') ifile,istart,xcmax,fc1,fcest
xdt=(istart-226)/100.0
if(abs(xdt).le.0.1) ngood=ngood+1
xs1=xs1+xdt
xs2=xs2+xdt**2
fr1=fr1+fc1
fr2=fr2+fc1**2
nav=nav+1
!**************
! fcest=0.0
! istart=226
do ijitter=0,2
io=ijitter
if(ijitter.eq.2) io=-1
cframe=c2(istart+io:istart+io+264*100-1)
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,cd)
dts=10*dt
s2=sum(cd*conjg(cd))/(10*264)
s2=sum(cd*conjg(cd))/(10*216)
cd=cd/sqrt(s2)
do nseq=1,7
if( nseq.eq.1 ) then ! noncoherent single-symbol detection
sbits1=0.0
do ibit=1,264
if( mod(ibit,2).eq.0 ) j=1
if( mod(ibit,2).eq.1 ) j=2
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)))
@ -334,19 +207,17 @@ do ijitter=0,2
if( nseq.eq. 6 ) nbit=11
if( nseq.eq. 7 ) nbit=13
numseq=2**(nbit)
do ibit=nbit/2+1,264-nbit/2
do ibit=nbit/2+1,216-nbit/2
ps=0.0
pmax=0.0
do iseq=0,numseq-1
csum=0.0
cterm=cmplx(1.0,0.0)
cterm=1.0
k=1
do i=nbit-1,0,-1
ibb=iand(iseq/(2**i),1)
csum=csum+ccor(ibb,ibit-(nbit/2+1)+k)*cterm
if( mod(ibit-(nbit/2+1)+k,2) .eq. 0 ) j=1
if( mod(ibit-(nbit/2+1)+k,2) .eq. 1 ) j=2
cterm=cterm*conjg(cp(ibb,j))
cterm=-cterm
k=k+1
enddo
ps(iseq)=abs(csum)
@ -366,7 +237,8 @@ do ijitter=0,2
sbits=sbits3
hbits=hbits3
endif
rxdata(1:200)=sbits(33:232)
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)
@ -401,6 +273,13 @@ do ijitter=0,2
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
@ -413,23 +292,138 @@ do ijitter=0,2
enddo ! nseq
enddo !jitter
888 continue
enddo !candidate list
enddo !files
avshift=xs1/nav
varshift=xs2/nav
stdshift=sqrt(varshift-avshift**2)
avfr=fr1/nav
varfr=fr2/nav
stdfr=sqrt(varfr-avfr**2)
write(*,*) 'ngood: ',ngood
write(*,'(a7,f7.3,f7.3)') 'shift: ',avshift,stdshift
write(*,*) 'freq: ',avfr,stdfr
write(*,1120)
1120 format("<DecodeFinished>")
999 end program wsprcpmd
subroutine coherent_preamble_fsync(c2,ipreamble,nsync,nsps,istart,fc0,fc1,xmax)
complex c2(0:120*12000/32-1)
complex cpreamble(0:16*200-1)
complex ctmp1(0:4*16*200-1)
complex ctwkp(0:16*200-1)
complex ccohp(0:15)
integer ipreamble(nsync)
logical first/.true./
save dt,first,h,twopi,cpreamble
if(first) then
baud=12000.0/6400.0
dt=32.0/12000.0
h=1.00
twopi=8.0*atan(1.0)
k=0
phi=0.0
dphi=twopi*baud*0.5*h*dt
do i=1,16
dp=dphi
if(ipreamble(i).eq.0) dp=-dphi
do j=1,200
cpreamble(k)=cmplx(cos(phi),sin(phi))
phi=mod(phi+dp,twopi)
k=k+1
enddo
enddo
first=.false.
endif
dphi=twopi*fc0*dt
ctwkp=cmplx(0.0,0.0)
phi=0
do i=0,nsync*nsps-1
ctwkp(i)=cpreamble(i)*cmplx(cos(phi),sin(phi))
phi=mod(phi+dphi,twopi)
enddo
ipstart=istart+100*200
ctmp1=0.0
ctmp1(0:16*200-1)=c2(ipstart:ipstart+16*200-1)*conjg(ctwkp)
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
xa=abs(ctmp1(i))
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
fc1=fc0+delta2
return
end subroutine coherent_preamble_fsync
subroutine noncoherent_frame_sync(c2,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)
h=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,10
! 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
ss=0.0
totp=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=sqrt(p0)
p1=sqrt(p1)
p2=sqrt(p2)
p3=sqrt(p3)
totp=totp+p0+p1+p2+p3
! cmet=(p1+p3)-(p0+p2)
cmet=max(p1,p3)-max(p0,p2) ! This works better near threshold SNR
if(isync2(is).eq.0) ss=ss-cmet
if(isync2(is).eq.1) ss=ss+cmet
enddo
ss=ss/totp
if(ss.gt.ssmax) then
ioffset=it
ssmax=ss
endif
enddo
istart=izero+ioffset
return
end subroutine noncoherent_frame_sync
subroutine getmetric2(ib,ps,ns,xmet)
real ps(0:ns-1)
xm1=0
@ -443,10 +437,10 @@ subroutine getmetric2(ib,ps,ns,xmet)
end subroutine getmetric2
subroutine downsample2(ci,f0,co)
parameter(NI=264*100,NH=NI/2,NO=NI/10) ! downsample from 100 samples per symbol to 10
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=12000.0/53.0
fs=12000.0/32.0
df=fs/NI
ct=ci
call four2a(ct,NI,1,-1,1) !c2c FFT to freq domain
@ -454,14 +448,10 @@ subroutine downsample2(ci,f0,co)
ct=cshift(ct,i0)
co=0.0
co(0)=ct(0)
! b=3.4*0.875/0.715
! b=2.6*0.5625/0.715
b=12.0
b=8.0
do i=1,NO/2
arg=(i*df/b)**2
filt=exp(-arg)
! filt=0.0
! if( i*df .le. b ) filt=1.0
co(i)=ct(i)*filt
co(NO-i)=ct(NI-i)*filt
enddo
@ -470,72 +460,62 @@ subroutine downsample2(ci,f0,co)
return
end subroutine downsample2
subroutine getcandidate2(c,npts,fs,fa,fb,fc1,xsnr)
parameter(NDAT=100,NFFT1=8*NDAT,NH1=NFFT1/2)
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 w(0:NFFT1-1)
real pi
real candidates(100,2)
integer indx(NFFT2-1)
logical first
data first/.true./
save first,w
save first,w,df,csfil
if(first) then
pi=4.0*atan(1.0)
do i=0,NFFT1-1
w(i)=sin(pi*i/(NDAT-1))**2
df=10*fs/NFFT1
csfil=cmplx(0.0,0.0)
do i=0,NFFT2-1
csfil(i)=exp(-((i-NH2)/20.0)**2)
enddo
csfil=cshift(csfil,NH2)
call four2a(csfil,NFFT2,1,-1,1)
first=.false.
endif
nspec=int((npts-NFFT1)/NDAT)+1
df1=fs/NFFT1
s=0.
do k=1,nspec
ia=(k-1)*NDAT
ib=ia+NFFT1-1
c2(0:NFFT1-1)=c(ia:ib)*w
call four2a(c2,NFFT1,1,-1,1)
do i=0,NFFT1-1
j=i
if(j.gt.NH1) j=j-NFFT1
s(j)=s(j) + real(c2(i))**2 + aimag(c2(i))**2
enddo
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.1.15).and.ncand.lt.100) then
ncand=ncand+1
candidates(ncand,1)=df*(i-NH2)
candidates(ncand,2)=10*log10(bigspec(i))-30.0
endif
enddo
do i=-NH1+1+4,NH1-4
ss(i)=sum(s(i-4:i+4))/9.0
enddo
! do i=-NH1+1+8,NH1-8
! ss(i)=sum(ss(i-4:i+4))/9.0
! do i=1,ncand
! write(*,*) i,candidates(i,1),candidates(i,2)
! enddo
do i=-20,20
write(52,*) i*df1,ss(i)
enddo
smax=0.
ipk=0
fc1=0.
ia=nint(fa/df1)
ib=nint(fb/df1)
do i=ia,ib
f=i*df1
if(ss(i).gt.smax) then
smax=ss(i)
ipk=i
fc1=f
endif
enddo
xint=(log(ss(ipk-1))-log(ss(ipk+1)))/(log(ss(ipk-1))+log(ss(ipk+1))-2*log(ss(ipk)))
fc1=fc1+xint*df1/2.0
! The following is for testing SNR calibration:
sp3n=sum(s(ipk-5:ipk+5))
base=(sum(s)-sp3n)/(NFFT1-11.0)
psig=sp3n-11*base
pnoise=(2500.0/df1)*base
xsnr=db(psig/pnoise)
return
end subroutine getcandidate2
@ -545,9 +525,9 @@ subroutine wsprcpm_downsample(iwave,c)
! Output: Complex data in c(), sampled at 400 Hz
include 'wsprcpm_params.f90'
parameter (NMAX=120*12000,NFFT2=NMAX/53)
parameter (NMAX=120*12000,NFFT2=NMAX/32)
integer*2 iwave(NMAX)
complex c(0:NZ-1)
complex c(0:NMAX/32-1)
complex c1(0:NFFT2-1)
complex cx(0:NMAX/2)
real x(NMAX)
@ -564,8 +544,7 @@ subroutine wsprcpm_downsample(iwave,c)
enddo
c1=c1/NFFT2
call four2a(c1,NFFT2,1,1,1) !c2c FFT back to time domain
c=c1(0:NZ-1)
c=c1(0:NMAX/32-1)
return
end subroutine wsprcpm_downsample

View File

@ -42,7 +42,6 @@ program wsprcpmsim
fs=12000.0/NDOWN !
dt=1.0/fs !Sample interval (s)
tt=NSPS*dt !Duration of "itone" symbols (s)
ts=2*NSPS*dt !Duration of OQPSK symbols (s)
baud=1.0/tt !Keying rate for "itone" symbols (baud)
txt=NZ*dt !Transmission length (s)
bandwidth_ratio=2500.0/(fs/2.0)
@ -55,25 +54,11 @@ program wsprcpmsim
1000 format('f0:',f9.3,' DT:',f6.2,' txt:',f6.1,' SNR:',f6.1, &
' fspread:',f6.1,' delay:',f6.1,' nfiles:',i3,2x,a22)
h1=0.80
h2=0.80
dphi11=twopi*(f0+(h1/2.0)*baud)*dt
dphi01=twopi*(f0-(h1/2.0)*baud)*dt
dphi12=twopi*(f0+(h2/2.0)*baud)*dt
dphi02=twopi*(f0-(h2/2.0)*baud)*dt
phi=0.0
h=1.00
c0=0.
k=-1 + nint(xdt/dt)
do j=1,NN
if( mod(j,2) .eq. 0 ) then
dphi1=dphi11
dphi0=dphi01
else
dphi1=dphi12
dphi0=dphi02
endif
dp=dphi1
if(itone(j).eq.-1) dp=dphi0
dp=twopi*(f0+itone(j)*(h/2.0)*baud)*dt
do i=1,NSPS
k=k+1
phi=mod(phi+dp,twopi)
@ -109,7 +94,7 @@ program wsprcpmsim
!write(57,*) i,real(c(i)),imag(c(i))
!enddo
else
call wsprcpm_wav(baud,xdt,h1,h2,f0,itone,snrdb,iwave)
call wsprcpm_wav(baud,xdt,h,f0,itone,snrdb,iwave)
hwav=default_header(12000,NMAX)
write(fname,1102) ifile
1102 format('000000_',i4.4,'.wav')