Add simulator (ft2sim.f90) and decoder (ft2d.f90) for experimental medium-fast mode.

This commit is contained in:
Steve Franke 2019-01-10 10:20:31 -06:00
parent 97e04fd7e1
commit e0658f183f
8 changed files with 631 additions and 197 deletions

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@ -459,6 +459,7 @@ set (wsjt_FSRCS
lib/ft8/genft8.f90
lib/genmsk_128_90.f90
lib/genmsk40.f90
lib/fsk4hf/genft2.f90
lib/genqra64.f90
lib/ft8/genft8refsig.f90
lib/genwspr.f90
@ -503,6 +504,8 @@ set (wsjt_FSRCS
lib/msk144signalquality.f90
lib/msk144sim.f90
lib/mskrtd.f90
lib/fsk4hf/ft2sim.f90
lib/fsk4hf/ft2d.f90
lib/77bit/my_hash.f90
lib/wsprd/osdwspr.f90
lib/ft8/osd174_91.f90
@ -1247,6 +1250,12 @@ target_link_libraries (ft8sim wsjt_fort wsjt_cxx)
add_executable (msk144sim lib/msk144sim.f90 wsjtx.rc)
target_link_libraries (msk144sim wsjt_fort wsjt_cxx)
add_executable (ft2sim lib/fsk4hf/ft2sim.f90 wsjtx.rc)
target_link_libraries (ft2sim wsjt_fort wsjt_cxx)
add_executable (ft2d lib/fsk4hf/ft2d.f90 wsjtx.rc)
target_link_libraries (ft2d wsjt_fort wsjt_cxx)
endif(WSJT_BUILD_UTILS)
# build the main application

12
lib/fsk4hf/ft2_params.f90 Normal file
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@ -0,0 +1,12 @@
! LDPC (128,90) code
parameter (KK=90) !Information bits (77 + CRC13)
parameter (ND=128) !Data symbols
parameter (NS=16) !Sync symbols (2x8)
parameter (NN=NS+ND) !Total channel symbols (144)
parameter (NSPS=160) !Samples per symbol at 12000 S/s
parameter (NZ=NSPS*NN) !Samples in full 1.92 s waveform (23040)
parameter (NMAX=3*12000) !Samples in iwave (36,000)
parameter (NFFT1=2*NSPS, NH1=NFFT1/2) !Length of FFTs for symbol spectra
parameter (NSTEP=NSPS/4) !Rough time-sync step size
parameter (NHSYM=NMAX/NSTEP-3) !Number of symbol spectra (1/4-sym steps)
parameter (NDOWN=10) !Downsample factor

325
lib/fsk4hf/ft2d.f90 Normal file
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@ -0,0 +1,325 @@
program ft2d
use crc
use packjt77
include 'ft2_params.f90'
character arg*8,message*37,c77*77,infile*80,fname*16,datetime*11
character*37 decodes(100)
character*120 data_dir
character*90 dmsg
complex c2(0:3*1200-1) !Complex waveform
complex cd(0:144*10-1) !Complex waveform
complex c1(0:9),c0(0:9)
complex ccor(0:1,144)
complex csum,cterm,cc0,cc1
real*8 fMHz
real rxdata(128),llr(128) !Soft symbols
real llr2(128)
real sbits(144),sbits1(144),sbits3(144)
real ps(0:8191),psbest(0:8191)
real candidates(100,2)
integer ihdr(11)
integer*2 iwave(NMAX) !Generated full-length waveform
integer*1 message77(77),apmask(128),cw(128)
integer*1 hbits(144),hbits1(144),hbits3(144)
logical unpk77_success
fs=12000.0/NDOWN !Sample rate
dt=1/fs !Sample interval after downsample (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)
twopi=8.0*atan(1.0)
h=0.8 !h=0.8 seems to be optimum for AWGN sensitivity (not for fading)
dphi=twopi/2*baud*h*dt*16 ! dt*16 is samp interval after downsample
dphi0=-1*dphi
dphi1=+1*dphi
phi0=0.0
phi1=0.0
do i=0,9
c1(i)=cmplx(cos(phi1),sin(phi1))
c0(i)=cmplx(cos(phi0),sin(phi0))
phi1=mod(phi1+dphi1,twopi)
phi0=mod(phi0+dphi0,twopi)
enddo
the=twopi*h/2.0
cc1=cmplx(cos(the),-sin(the))
cc0=cmplx(cos(the),sin(the))
nargs=iargc()
if(nargs.lt.1) then
print*,'Usage: ft2d [-a <data_dir>] [-f fMHz] [-c ncoh] 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
npdi=16
if(arg(1:2).eq.'-c') then
call getarg(iarg+1,arg)
read(arg,*) ncoh
iarg=iarg+2
npdi=16/ncoh
endif
! write(*,*) 'ncoh: ',ncoh,' npdi: ',npdi
xs1=0.0
xs2=0.0
fr1=0.0
fr2=0.0
nav=0
ngood=0
do ifile=iarg,nargs
call getarg(ifile,infile)
j2=index(infile,'.wav')
open(10,file=infile,status='old',access='stream')
read(10,end=999) ihdr,iwave
read(infile(j2-4:j2-1),*) nutc
datetime=infile(j2-11:j2-1)
close(10)
ndecodes=0
ncand=1
do icand=1,ncand
fc0=1500.0
xsnr=1.0
istart=6000+8
call ft2_downsample(iwave,c2) ! downsample from 160s/Symbol to 10s/Symbol
ib=istart/16
cd=c2(ib:ib+144*10-1)
s2=sum(cd*conjg(cd))/(10*144)
cd=cd/sqrt(s2)
do nseq=1,7
if( nseq.eq.1 ) then ! noncoherent single-symbol detection
sbits1=0.0
do ibit=1,144
ib=(ibit-1)*10
ccor(1,ibit)=sum(cd(ib:ib+9)*conjg(c1(0:9)))
ccor(0,ibit)=sum(cd(ib:ib+9)*conjg(c0(0:9)))
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
nbit=2*nseq-1
numseq=2**(nbit)
ps=0
do ibit=nbit/2+1,144-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
ibb=iand(iseq/(2**i),1)
csum=csum+ccor(ibb,ibit-(nbit/2+1)+k)*cterm
if(ibb.eq.0) cterm=cterm*cc0
if(ibb.eq.1) cterm=cterm*cc1
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 getbitmetric(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(1:48)=sbits(9:56)
rxdata(49:128)=sbits(65:144)
rxav=sum(rxdata(1:128))/128.0
rx2av=sum(rxdata(1:128)*rxdata(1:128))/128.0
rxsig=sqrt(rx2av-rxav*rxav)
rxdata=rxdata/rxsig
sigma=0.90
llr(1:128)=2*rxdata/(sigma*sigma)
apmask=0
max_iterations=40
ifer=0
do ibias=0,0
llr2=llr
if(ibias.eq.1) llr2=llr+0.4
if(ibias.eq.2) llr2=llr-0.4
call bpdecode128_90(llr2,apmask,max_iterations,message77,cw,nharderror,niterations)
if(nharderror.ge.0) exit
enddo
nhardmin=-1
if(sum(message77).eq.0) cycle
if( nharderror.ge.0 ) then
write(c77,'(77i1)') message77(1:77)
call unpack77(c77,message,unpk77_success)
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)
1210 format(a11,2i4,f6.2,f12.7,2x,a22,i3)
write(*,1212) datetime(8:11),nsnr,xdt,freq,message,'*',idf,nseq,ijitter,nharderror,nhardmin
1212 format(a4,i4,f5.1,f11.6,2x,a22,a1,i5,i5,i5,i5,i5)
goto 888
endif
enddo ! nseq
888 continue
enddo !candidate list
enddo !files
write(*,1120)
1120 format("<DecodeFinished>")
999 end program ft2d
subroutine getbitmetric(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 getbitmetric
subroutine downsample2(ci,f0,co)
parameter(NI=144*160,NH=NI/2,NO=NI/16) ! 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
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=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)/20.0)**2)
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.1.15).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=1,ncand
! write(*,*) i,candidates(i,1),candidates(i,2)
! enddo
return
end subroutine getcandidate2
subroutine ft2_downsample(iwave,c)
! Input: i*2 data in iwave() at sample rate 12000 Hz
! Output: Complex data in c(), sampled at 1200 Hz
include 'ft2_params.f90'
parameter (NFFT2=NMAX/16)
integer*2 iwave(NMAX)
complex c(0:NMAX/16-1)
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/16-1)
return
end subroutine ft2_downsample

139
lib/fsk4hf/ft2sim.f90 Normal file
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@ -0,0 +1,139 @@
program ft2sim
! Generate simulated signals for experimental "FT2" mode
use wavhdr
use packjt77
include 'ft2_params.f90' !Set various constants
parameter (NWAVE=NN*NSPS)
type(hdr) h !Header for .wav file
character arg*12,fname*17
character msg37*37,msgsent37*37
character c77*77
complex c0(0:NMAX-1)
complex c(0:NMAX-1)
real wave(NMAX)
integer itone(NN)
integer*1 msgbits(77)
integer*2 iwave(NMAX) !Generated full-length waveform
! Get command-line argument(s)
nargs=iargc()
if(nargs.ne.8) then
print*,'Usage: ft2sim "message" f0 DT fdop del width nfiles snr'
print*,'Examples: ft2sim "K1ABC W9XYZ EN37" 1500.0 0.0 0.1 1.0 0 10 -18'
print*,' ft2sim "WA9XYZ/R KA1ABC/R FN42" 1500.0 0.0 0.1 1.0 0 10 -18'
print*,' ft2sim "K1ABC RR73; W9XYZ <KH1/KH7Z> -11" 300 0 0 0 25 1 -10'
go to 999
endif
call getarg(1,msg37) !Message to be transmitted
call getarg(2,arg)
read(arg,*) f0 !Frequency (only used for single-signal)
call getarg(3,arg)
read(arg,*) xdt !Time offset from nominal (s)
call getarg(4,arg)
read(arg,*) fspread !Watterson frequency spread (Hz)
call getarg(5,arg)
read(arg,*) delay !Watterson delay (ms)
call getarg(6,arg)
read(arg,*) width !Filter transition width (Hz)
call getarg(7,arg)
read(arg,*) nfiles !Number of files
call getarg(8,arg)
read(arg,*) snrdb !SNR_2500
nsig=1
if(f0.lt.100.0) then
nsig=f0
f0=1500
endif
nfiles=abs(nfiles)
twopi=8.0*atan(1.0)
fs=12000.0 !Sample rate (Hz)
dt=1.0/fs !Sample interval (s)
hmod=0.8 !Modulation index (0.5 is MSK, 1.0 is FSK)
tt=NSPS*dt !Duration of symbols (s)
baud=1.0/tt !Keying rate (baud)
bw=1.5*baud !Occupied bandwidth (Hz)
txt=NZ*dt !Transmission length (s)
bandwidth_ratio=2500.0/(fs/2.0)
sig=sqrt(2*bandwidth_ratio) * 10.0**(0.05*snrdb)
if(snrdb.gt.90.0) sig=1.0
txt=NN*NSPS/12000.0
! Source-encode, then get itone()
i3=-1
n3=-1
call pack77(msg37,i3,n3,c77)
read(c77,'(77i1)') msgbits
call genft2(msg37,0,msgsent37,itone,itype)
write(*,*)
write(*,'(a9,a37,3x,a7,i1,a1,i1)') 'Message: ',msgsent37,'i3.n3: ',i3,'.',n3
write(*,1000) f0,xdt,txt,snrdb,bw
1000 format('f0:',f9.3,' DT:',f6.2,' TxT:',f6.1,' SNR:',f6.1, &
' BW:',f5.1)
write(*,*)
if(i3.eq.1) then
write(*,*) ' mycall hiscall hisgrid'
write(*,'(28i1,1x,i1,1x,28i1,1x,i1,1x,i1,1x,15i1,1x,3i1)') msgbits(1:77)
else
write(*,'(a14)') 'Message bits: '
write(*,'(77i1)') msgbits
endif
write(*,*)
write(*,'(a17)') 'Channel symbols: '
write(*,'(79i1)') itone
write(*,*)
call sgran()
do ifile=1,nfiles
k=nint((xdt+0.5)/dt)
ia=k
phi=0.0
c0=0.0
do j=1,NN !Generate complex waveform
dphi=twopi*(f0*dt+(hmod/2.0)*(2*itone(j)-1)/real(NSPS))
do i=1,NSPS
if(k.ge.0 .and. k.lt.NMAX) c0(k)=cmplx(cos(phi),sin(phi))
k=k+1
phi=mod(phi+dphi,twopi)
enddo
enddo
if(fspread.ne.0.0 .or. delay.ne.0.0) call watterson(c0,NMAX,NWAVE,fs,delay,fspread)
c=sig*c0
ib=k
wave=real(c)
peak=maxval(abs(wave(ia:ib)))
nslots=1
if(width.gt.0.0) call filt8(f0,nslots,width,wave)
if(snrdb.lt.90) then
do i=1,NMAX !Add gaussian noise at specified SNR
xnoise=gran()
wave(i)=wave(i) + xnoise
enddo
endif
gain=100.0
if(snrdb.lt.90.0) then
wave=gain*wave
else
datpk=maxval(abs(wave))
fac=32766.9/datpk
wave=fac*wave
endif
if(any(abs(wave).gt.32767.0)) print*,"Warning - data will be clipped."
iwave=nint(wave)
h=default_header(12000,NMAX)
write(fname,1102) ifile
1102 format('000000_',i6.6,'.wav')
open(10,file=fname,status='unknown',access='stream')
write(10) h,iwave !Save to *.wav file
close(10)
write(*,1110) ifile,xdt,f0,snrdb,fname
1110 format(i4,f7.2,f8.2,f7.1,2x,a17)
enddo
999 end program ft2sim

124
lib/fsk4hf/genft2.f90 Normal file
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@ -0,0 +1,124 @@
subroutine genft2(msg0,ichk,msgsent,i4tone,itype)
! s8 + 48bits + s8 + 80 bits = 144 bits (72ms message duration)
!
! Encode an MSK144 message
! Input:
! - msg0 requested message to be transmitted
! - ichk if ichk=1, return only msgsent
! if ichk.ge.10000, set imsg=ichk-10000 for short msg
! - msgsent message as it will be decoded
! - i4tone array of audio tone values, 0 or 1
! - itype message type
! 1 = standard message "Call_1 Call_2 Grid/Rpt"
! 2 = type 1 prefix
! 3 = type 1 suffix
! 4 = type 2 prefix
! 5 = type 2 suffix
! 6 = free text (up to 13 characters)
! 7 = short message "<Call_1 Call2> Rpt"
use iso_c_binding, only: c_loc,c_size_t
use packjt77
character*37 msg0
character*37 message !Message to be generated
character*37 msgsent !Message as it will be received
character*77 c77
integer*4 i4tone(144)
integer*1 codeword(128)
integer*1 msgbits(77)
integer*1 bitseq(144) !Tone #s, data and sync (values 0-1)
integer*1 s8(8)
real*8 pp(12)
real*8 xi(864),xq(864),pi,twopi
data s8/0,1,1,1,0,0,1,0/
equivalence (ihash,i1hash)
logical first,unpk77_success
data first/.true./
save
if(first) then
first=.false.
nsym=128
pi=4.0*atan(1.0)
twopi=8.*atan(1.0)
do i=1,12
pp(i)=sin((i-1)*pi/12)
enddo
endif
message(1:37)=' '
itype=1
if(msg0(1:1).eq.'@') then !Generate a fixed tone
read(msg0(2:5),*,end=1,err=1) nfreq !at specified frequency
go to 2
1 nfreq=1000
2 i4tone(1)=nfreq
else
message=msg0
do i=1, 37
if(ichar(message(i:i)).eq.0) then
message(i:37)=' '
exit
endif
enddo
do i=1,37 !Strip leading blanks
if(message(1:1).ne.' ') exit
message=message(i+1:)
enddo
if(message(1:1).eq.'<') then
i2=index(message,'>')
i1=0
if(i2.gt.0) i1=index(message(1:i2),' ')
if(i1.gt.0) then
call genmsk40(message,msgsent,ichk,i4tone,itype)
if(itype.lt.0) go to 999
i4tone(41)=-40
go to 999
endif
endif
i3=-1
n3=-1
call pack77(message,i3,n3,c77)
call unpack77(c77,msgsent,unpk77_success) !Unpack to get msgsent
if(ichk.eq.1) go to 999
read(c77,"(77i1)") msgbits
call encode_128_90(msgbits,codeword)
!Create 144-bit channel vector:
!8-bit sync word + 48 bits + 8-bit sync word + 80 bits
bitseq=0
bitseq(1:8)=s8
bitseq(9:56)=codeword(1:48)
bitseq(57:64)=s8
bitseq(65:144)=codeword(49:128)
i4tone=bitseq
! bitseq=2*bitseq-1
! xq(1:6)=bitseq(1)*pp(7:12) !first bit is mapped to 1st half-symbol on q
! do i=1,71
! is=(i-1)*12+7
! xq(is:is+11)=bitseq(2*i+1)*pp
! enddo
! xq(864-5:864)=bitseq(1)*pp(1:6) !last half symbol
! do i=1,72
! is=(i-1)*12+1
! xi(is:is+11)=bitseq(2*i)*pp
! enddo
! Map I and Q to tones.
! i4tone=0
! do i=1,72
! i4tone(2*i-1)=(bitseq(2*i)*bitseq(2*i-1)+1)/2;
! i4tone(2*i)=-(bitseq(2*i)*bitseq(mod(2*i,144)+1)-1)/2;
! enddo
endif
! Flip polarity
! i4tone=-i4tone+1
999 return
end subroutine genft2

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@ -1,194 +0,0 @@
program msksim
! Simulate characteristics of a potential "MSK10" mode using LDPC (168,84)
! code, OQPDK modulation, and 30 s T/R sequences.
! Reception and Demodulation algorithm:
! 1. Compute coarse spectrum; find fc1 = approx carrier freq
! 2. Mix from fc1 to 0; LPF at +/- 0.75*R
! 3. Square, FFT; find peaks near -R/2 and +R/2 to get fc2
! 4. Mix from fc2 to 0
! 5. Fit cb13 (central part of csync) to c -> lag, phase
! 6. Fit complex ploynomial for channel equalization
! 7. Get soft bits from equalized data
parameter (KK=84) !Information bits (72 + CRC12)
parameter (ND=168) !Data symbols: LDPC (168,84), r=1/2
parameter (NS=65) !Sync symbols (2 x 26 + Barker 13)
parameter (NR=3) !Ramp up/down
parameter (NN=NR+NS+ND) !Total symbols (236)
parameter (NSPS=1152/72) !Samples per MSK symbol (16)
parameter (N2=2*NSPS) !Samples per OQPSK symbol (32)
parameter (N13=13*N2) !Samples in central sync vector (416)
parameter (NZ=NSPS*NN) !Samples in baseband waveform (3776)
parameter (NFFT1=4*NSPS,NH1=NFFT1/2)
character*8 arg
complex cbb(0:NZ-1) !Complex baseband waveform
complex csync(0:NZ-1) !Sync symbols only, from cbb
complex cb13(0:N13-1) !Barker 13 waveform
complex c(0:NZ-1) !Complex waveform
complex c0(0:NZ-1) !Complex waveform
complex zz(NS+ND) !Complex symbol values (intermediate)
complex z
real xnoise(0:NZ-1) !Generated random noise
real ynoise(0:NZ-1) !Generated random noise
real rxdata(ND),llr(ND) !Soft symbols
real pp(2*NSPS) !Shaped pulse for OQPSK
real a(5) !For twkfreq1
real aa(20),bb(20) !Fitted polyco's
integer id(NS+ND) !NRZ values (+/-1) for Sync and Data
integer ierror(NS+ND)
integer icw(NN)
integer*1 msgbits(KK),decoded(KK),apmask(ND),cw(ND)
! integer*1 codeword(ND)
data msgbits/0,0,1,0,0,1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,1,1,0,0,0,1, &
1,1,1,0,1,1,1,1,1,1,1,0,0,1,0,0,1,1,0,1,0,1,1,1,0,1,1,0,1,1, &
1,1,0,1,0,1,1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,1,0/
nargs=iargc()
if(nargs.ne.6) then
print*,'Usage: mskhfsim f0(Hz) delay(ms) fspread(Hz) maxn iters snr(dB)'
print*,'Example: mskhfsim 0 0 0 5 10 -20'
print*,'Set snr=0 to cycle through a range'
go to 999
endif
call getarg(1,arg)
read(arg,*) f0 !Generated carrier frequency
call getarg(2,arg)
read(arg,*) delay !Delta_t (ms) for Watterson model
call getarg(3,arg)
read(arg,*) fspread !Fspread (Hz) for Watterson model
call getarg(4,arg)
read(arg,*) maxn !Max nterms for polyfit
call getarg(5,arg)
read(arg,*) iters !Iterations at each SNR
call getarg(6,arg)
read(arg,*) snrdb !Specified SNR_2500
twopi=8.0*atan(1.0)
fs=12000.0/72.0 !Sample rate = 166.6666667 Hz
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)
write(*,1000) f0,delay,fspread,maxn,iters,baud,3*baud,txt
1000 format('f0:',f5.1,' Delay:',f4.1,' fSpread:',f5.2,' maxn:',i3, &
' Iters:',i6/'Baud:',f7.3,' BW:',f5.1,' TxT:',f5.1,f5.2/)
write(*,1004)
1004 format(/' SNR err ber fer fsigma'/37('-'))
do i=1,N2 !Half-sine pulse shape
pp(i)=sin(0.5*(i-1)*twopi/(2*NSPS))
enddo
call genmskhf(msgbits,id,icw,cbb,csync)!Generate baseband waveform and csync
cb13=csync(1680:2095) !Copy the Barker 13 waveform
a=0.
a(1)=f0
call twkfreq1(cbb,NZ,fs,a,cbb) !Mix to specified frequency
isna=-10
isnb=-30
if(snrdb.ne.0.0) then
isna=nint(snrdb)
isnb=isna
endif
do isnr=isna,isnb,-1 !Loop over SNR range
snrdb=isnr
sig=sqrt(bandwidth_ratio) * 10.0**(0.05*snrdb)
if(snrdb.gt.90.0) sig=1.0
nhard=0
nhardsync=0
nfe=0
sqf=0.
do iter=1,iters !Loop over requested iterations
c=cbb
if(delay.ne.0.0 .or. fspread.ne.0.0) then
call watterson(c,NZ,fs,delay,fspread)
endif
c=sig*c !Scale to requested SNR
if(snrdb.lt.90) then
do i=0,NZ-1 !Generate gaussian noise
xnoise(i)=gran()
ynoise(i)=gran()
enddo
c=c + cmplx(xnoise,ynoise) !Add AWGN noise
endif
call getfc1(c,fc1) !First approx for freq
call getfc2(c,csync,fc1,fc2,fc3) !Refined freq
sqf=sqf + (fc1+fc2-f0)**2
!NB: Measured performance is about equally good using fc2 or fc3 here:
a(1)=-(fc1+fc2)
a(2:5)=0.
call twkfreq1(c,NZ,fs,a,c) !Mix c down by fc1+fc2
! The following may not be necessary?
! z=sum(c(1680:2095)*cb13)/208.0 !Get phase from Barker 13 vector
! z0=z/abs(z)
! c=c*conjg(z0)
!---------------------------------------------------------------- DT
! Not presently used:
amax=0.
jpk=0
do j=-20*NSPS,20*NSPS !Get jpk
z=sum(c(1680+j:2095+j)*cb13)/208.0
if(abs(z).gt.amax) then
amax=abs(z)
jpk=j
endif
enddo
xdt=jpk/fs
nterms=maxn
c0=c
do itry=1,10
idf=itry/2
if(mod(itry,2).eq.0) idf=-idf
nhard0=0
nhardsync0=0
ifer=1
a(1)=idf*0.01
a(2:5)=0.
call twkfreq1(c0,NZ,fs,a,c) !Mix c0 into c
call cpolyfit(c,pp,id,maxn,aa,bb,zz,nhs)
call msksoftsym(zz,aa,bb,id,nterms,ierror,rxdata,nhard0,nhardsync0)
if(nhardsync0.gt.12) cycle
rxav=sum(rxdata)/ND
rx2av=sum(rxdata*rxdata)/ND
rxsig=sqrt(rx2av-rxav*rxav)
rxdata=rxdata/rxsig
ss=0.84
llr=2.0*rxdata/(ss*ss)
apmask=0
max_iterations=40
ifer=0
call bpdecode168(llr,apmask,max_iterations,decoded,niterations,cw)
nbadcrc=0
if(niterations.ge.0) call chkcrc12(decoded,nbadcrc)
if(niterations.lt.0 .or. count(msgbits.ne.decoded).gt.0 .or. &
nbadcrc.ne.0) ifer=1
! if(ifer.eq.0) write(67,1301) snrdb,itry,idf,niterations, &
! nhardsync0,nhard0
!1301 format(f6.1,5i6)
if(ifer.eq.0) exit
enddo !Freq dither loop
nhard=nhard+nhard0
nhardsync=nharsdync+nhardsync0
nfe=nfe+ifer
enddo
fsigma=sqrt(sqf/iters)
ber=float(nhard)/((NS+ND)*iters)
fer=float(nfe)/iters
write(*,1050) snrdb,nhard,ber,fer,fsigma
! write(60,1050) snrdb,nhard,ber,fer,fsigma
1050 format(f6.1,i7,f8.4,f7.3,f8.2)
enddo
999 end program msksim

View File

@ -70,14 +70,14 @@ endfunction
# M-ary PSK Block Coded Modulation," Igal Sason and Gil Weichman,
# doi: 10.1109/EEEI.2006.321097
#-------------------------------------------------------------------------------
N=174
K=75
N=128
K=90
R=K/N
delta=0.01;
[ths,fval,info,output]=fzero(@f1,[delta,pi/2-delta], optimset ("jacobian", "off"));
for ebnodb=-6:0.5:4
for ebnodb=-3:0.5:4
ebno=10^(ebnodb/10.0);
esno=ebno*R;
A=sqrt(2*esno);

19
lib/fsk4hf/spb_128_90.dat Normal file
View File

@ -0,0 +1,19 @@
N = 128
K = 90
R = 0.70312
-3.000000 0.000341
-2.500000 0.001513
-2.000000 0.006049
-1.500000 0.021280
-1.000000 0.064283
-0.500000 0.162755
0.000000 0.338430
0.500000 0.571867
1.000000 0.791634
1.500000 0.930284
2.000000 0.985385
2.500000 0.998258
3.000000 0.999893
3.500000 0.999997
4.000000 1.000000