2020-04-26 14:34:09 -05:00
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program ft4sd
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! Decode ft4slow data read from *.c2 or *.wav files.
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use packjt77
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include 'ft4s_params.f90'
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parameter (NSPS2=NSPS/32)
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character arg*8,cbits*50,infile*80,fname*16,datetime*11
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character ch1*1,ch4*4,cseq*31
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character*22 decodes(100)
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character*37 msg
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character*120 data_dir
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character*77 c77
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complex c2(0:NMAX/32-1) !Complex waveform
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complex cframe(0:144*NSPS2-1) !Complex waveform
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complex cd(0:144*20-1) !Complex waveform
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real*8 fMHz
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real llr(240),llra(240),llrb(240),llrc(240),llrd(240)
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real candidates(100,2)
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real bitmetrics(288,4)
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integer ihdr(11)
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integer*2 iwave(NMAX) !Generated full-length waveform
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integer*1 apmask(240),cw(240)
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integer*1 hbits(288)
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integer*1 message101(101)
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logical badsync,unpk77_success
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fs=12000.0/NDOWN !Sample rate
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dt=1.0/fs !Sample interval (s)
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tt=NSPS*dt !Duration of "itone" symbols (s)
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txt=NZ*dt !Transmission length (s)
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2020-04-28 07:21:13 -05:00
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hmod=1.0
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2020-05-02 08:10:35 -05:00
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Keff=91
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2020-04-26 14:34:09 -05:00
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nargs=iargc()
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if(nargs.lt.1) then
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2020-05-02 08:10:35 -05:00
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print*,'Usage: ft4sd [-a <data_dir>] [-f fMHz] [-h hmod] [-k Keff] file1 [file2 ...]'
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2020-04-26 14:34:09 -05:00
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go to 999
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endif
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iarg=1
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data_dir="."
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call getarg(iarg,arg)
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if(arg(1:2).eq.'-a') then
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call getarg(iarg+1,data_dir)
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iarg=iarg+2
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2020-05-02 08:10:35 -05:00
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call getarg(iarg,arg)
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2020-04-26 14:34:09 -05:00
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endif
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if(arg(1:2).eq.'-f') then
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call getarg(iarg+1,arg)
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read(arg,*) fMHz
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iarg=iarg+2
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2020-05-02 08:10:35 -05:00
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call getarg(iarg,arg)
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2020-04-26 14:34:09 -05:00
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endif
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2020-04-28 07:21:13 -05:00
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if(arg(1:2).eq.'-h') then
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call getarg(iarg+1,arg)
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read(arg,*) hmod
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iarg=iarg+2
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2020-05-02 08:10:35 -05:00
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call getarg(iarg,arg)
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endif
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if(arg(1:2).eq.'-k') then
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call getarg(iarg+1,arg)
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read(arg,*) Keff
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iarg=iarg+2
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2020-04-28 07:21:13 -05:00
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endif
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2020-04-26 14:34:09 -05:00
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ngood=0
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do ifile=iarg,nargs
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call getarg(ifile,infile)
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open(10,file=infile,status='old',access='stream')
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j1=index(infile,'.c2')
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j2=index(infile,'.wav')
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if(j1.gt.0) then
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read(10,end=999) fname,ntrmin,fMHz,c2
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read(fname(8:11),*) nutc
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write(datetime,'(i11)') nutc
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else if(j2.gt.0) then
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read(10,end=999) ihdr,iwave
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read(infile(j2-4:j2-1),*) nutc
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datetime=infile(j2-11:j2-1)
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call ft4s_downsample(iwave,c2)
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else
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print*,'Wrong file format?'
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go to 999
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endif
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close(10)
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fa=-100.0
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fb=100.0
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fs=12000.0/32.0
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npts=120*12000.0/32.0
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2020-04-28 07:21:13 -05:00
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call getcandidate_ft4s(c2,npts,hmod,fs,fa,fb,ncand,candidates) !First approx for freq
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2020-04-26 14:34:09 -05:00
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2020-04-28 07:21:13 -05:00
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del=1.5*hmod*fs/300.0
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2020-04-26 14:34:09 -05:00
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ndecodes=0
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do icand=1,ncand
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fc0=candidates(icand,1)
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xsnr=candidates(icand,2)
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!write(*,*) 'candidates ',icand,fc0,xsnr
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do isync=0,1
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if(isync.eq.0) then
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fc1=fc0-del
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is0=375
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ishw=350
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isst=30
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ifhw=10
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df=.1
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else if(isync.eq.1) then
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fc1=fc2
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is0=isbest
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ishw=100
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isst=10
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ifhw=10
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df=.02
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endif
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smax=0.0
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do if=-ifhw,ifhw
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fc=fc1+df*if
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do istart=max(1,is0-ishw),is0+ishw,isst
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2020-04-28 07:21:13 -05:00
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call coherent_sync_ft4s(c2,istart,hmod,fc,1,sync)
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2020-04-26 14:34:09 -05:00
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if(sync.gt.smax) then
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fc2=fc
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isbest=istart
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smax=sync
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endif
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enddo
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enddo
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! write(*,*) ifile,icand,isync,fc1+del,fc2+del,isbest,smax
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enddo
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! if(smax .lt. 100.0 ) cycle
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!isbest=375
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2020-05-02 08:10:35 -05:00
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!fc2=-del
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2020-04-26 14:34:09 -05:00
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do ijitter=0,2
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if(ijitter.eq.0) ioffset=0
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if(ijitter.eq.1) ioffset=45
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if(ijitter.eq.2) ioffset=-45
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is0=isbest+ioffset
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if(is0.lt.0) cycle
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cframe=c2(is0:is0+144*300-1)
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2020-04-28 07:21:13 -05:00
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call downsample_ft4s(cframe,fc2+del,hmod,cd)
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2020-04-26 14:34:09 -05:00
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s2=sum(cd*conjg(cd))/(20*144)
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cd=cd/sqrt(s2)
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2020-04-28 07:21:13 -05:00
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call get_ft4s_bitmetrics(cd,hmod,bitmetrics,badsync)
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2020-04-26 14:34:09 -05:00
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hbits=0
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where(bitmetrics(:,1).ge.0) hbits=1
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ns1=count(hbits( 1: 8).eq.(/0,0,0,1,1,0,1,1/))
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ns2=count(hbits( 57: 64).eq.(/0,1,0,0,1,1,1,0/))
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ns3=count(hbits(113:120).eq.(/1,1,1,0,0,1,0,0/))
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ns4=count(hbits(169:176).eq.(/1,0,1,1,0,0,0,1/))
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ns5=count(hbits(225:232).eq.(/0,0,1,1,1,0,0,1/))
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ns6=count(hbits(281:288).eq.(/0,1,1,1,0,0,1,0/))
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nsync_qual=ns1+ns2+ns3+ns4+ns5+ns6
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! if(nsync_qual.lt. 20) cycle
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scalefac=2.83
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llra( 1: 48)=bitmetrics( 9: 56, 1)
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llra( 49: 96)=bitmetrics( 65:112, 1)
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llra( 97:144)=bitmetrics(121:168, 1)
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llra(145:192)=bitmetrics(177:224, 1)
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llra(193:240)=bitmetrics(233:280, 1)
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llra=scalefac*llra
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llrb( 1: 48)=bitmetrics( 9: 56, 2)
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llrb( 49: 96)=bitmetrics( 65:112, 2)
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llrb( 97:144)=bitmetrics(121:168, 2)
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llrb(145:192)=bitmetrics(177:224, 2)
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llrb(193:240)=bitmetrics(233:280, 2)
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llrb=scalefac*llrb
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llrc( 1: 48)=bitmetrics( 9: 56, 3)
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llrc( 49: 96)=bitmetrics( 65:112, 3)
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llrc( 97:144)=bitmetrics(121:168, 3)
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llrc(145:192)=bitmetrics(177:224, 3)
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llrc(193:240)=bitmetrics(233:280, 3)
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llrc=scalefac*llrc
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llrd( 1: 48)=bitmetrics( 9: 56, 4)
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llrd( 49: 96)=bitmetrics( 65:112, 4)
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llrd( 97:144)=bitmetrics(121:168, 4)
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llrd(145:192)=bitmetrics(177:224, 4)
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llrd(193:240)=bitmetrics(233:280, 4)
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llrd=scalefac*llrd
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apmask=0
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max_iterations=40
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do itry=4,1,-1
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if(itry.eq.1) llr=llra
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if(itry.eq.2) llr=llrb
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if(itry.eq.3) llr=llrc
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if(itry.eq.4) llr=llrd
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nhardbp=0
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nhardosd=0
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dmin=0.0
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call bpdecode240_101(llr,apmask,max_iterations,message101,cw,nhardbp,niterations,nchecks)
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! if(nhardbp.lt.0) call osd240_101(llr,Keff,apmask,5,message101,cw,nhardosd,dmin)
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maxsuperits=2
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ndeep=3 ! use ndeep=3 with Keff=91
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2020-05-02 08:10:35 -05:00
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if(Keff.eq.77) ndeep=4
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2020-04-26 14:34:09 -05:00
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if(nhardbp.lt.0) then
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! call osd240_101(llr,Keff,apmask,ndeep,message101,cw,nhardosd,dmin)
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call decode240_101(llr,Keff,ndeep,apmask,maxsuperits,message101,cw,nhardosd,iter,ncheck,dmin,isuper)
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endif
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if(nhardbp.ge.0 .or. nhardosd.ge.0) then
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write(c77,'(77i1)') message101(1:77)
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call unpack77(c77,0,msg,unpk77_success)
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if(unpk77_success .and. index(msg,'K9AN').gt.0) then
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ngood=ngood+1
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2020-04-28 07:21:13 -05:00
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write(*,1100) ifile-2,icand,xsnr,isbest/375.0-1.0,1500.0+fc2+del,msg(1:20),itry,nhardbp,nhardosd,dmin,ijitter
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1100 format(i5,2x,i5,2x,f6.1,2x,f6.2,2x,f8.2,2x,a20,i4,i4,i4,f7.2,i6)
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2020-04-26 14:34:09 -05:00
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goto 2002
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else
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cycle
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endif
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endif
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enddo ! metrics
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enddo ! istart jitter
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enddo !candidate list
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2002 continue
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enddo !files
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nfiles=nargs-iarg+1
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write(*,*) 'nfiles: ',nfiles,' ngood: ',ngood
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write(*,1120)
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1120 format("<DecodeFinished>")
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999 end program ft4sd
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2020-04-28 07:21:13 -05:00
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subroutine coherent_sync_ft4s(cd0,i0,hmod,f0,itwk,sync)
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2020-04-26 14:34:09 -05:00
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! Compute sync power for a complex, downsampled FT4s signal.
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include 'ft4s_params.f90'
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parameter(NP=NMAX/NDOWN,NSS=NSPS/NDOWN)
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complex cd0(0:NP-1)
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complex csynca(4*NSS),csyncb(4*NSS)
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complex csyncc(4*NSS),csyncd(4*NSS)
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complex csynce(4*NSS),csyncf(4*NSS)
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complex csync2(4*NSS)
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complex ctwk(4*NSS)
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complex z1,z2,z3,z4,z5,z6
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logical first
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integer icos4a(0:3),icos4b(0:3)
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integer icos4c(0:3),icos4d(0:3)
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integer icos4e(0:3),icos4f(0:3)
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data icos4a/0,1,3,2/
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data icos4b/1,0,2,3/
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data icos4c/2,3,1,0/
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data icos4d/3,2,0,1/
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data icos4e/0,2,3,1/
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data icos4f/1,2,0,3/
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data first/.true./
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save first,twopi,csynca,csyncb,csyncc,csyncd,csynce,csyncf,fac
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p(z1)=(real(z1*fac)**2 + aimag(z1*fac)**2)**0.5 !Statement function for power
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if( first ) then
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twopi=8.0*atan(1.0)
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k=1
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phia=0.0
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phib=0.0
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phic=0.0
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phid=0.0
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phie=0.0
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phif=0.0
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do i=0,3
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2020-04-28 07:21:13 -05:00
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dphia=twopi*hmod*icos4a(i)/real(NSS)
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dphib=twopi*hmod*icos4b(i)/real(NSS)
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dphic=twopi*hmod*icos4c(i)/real(NSS)
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dphid=twopi*hmod*icos4d(i)/real(NSS)
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dphie=twopi*hmod*icos4e(i)/real(NSS)
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dphif=twopi*hmod*icos4f(i)/real(NSS)
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2020-04-26 14:34:09 -05:00
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do j=1,NSS
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csynca(k)=cmplx(cos(phia),sin(phia))
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csyncb(k)=cmplx(cos(phib),sin(phib))
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csyncc(k)=cmplx(cos(phic),sin(phic))
|
|
|
|
|
csyncd(k)=cmplx(cos(phid),sin(phid))
|
|
|
|
|
csynce(k)=cmplx(cos(phie),sin(phie))
|
|
|
|
|
csyncf(k)=cmplx(cos(phif),sin(phif))
|
|
|
|
|
phia=mod(phia+dphia,twopi)
|
|
|
|
|
phib=mod(phib+dphib,twopi)
|
|
|
|
|
phic=mod(phic+dphic,twopi)
|
|
|
|
|
phid=mod(phid+dphid,twopi)
|
|
|
|
|
phie=mod(phie+dphie,twopi)
|
|
|
|
|
phif=mod(phif+dphif,twopi)
|
|
|
|
|
k=k+1
|
|
|
|
|
enddo
|
|
|
|
|
enddo
|
|
|
|
|
first=.false.
|
|
|
|
|
fac=1.0/(4.0*NSS)
|
|
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
i1=i0 !four Costas arrays
|
|
|
|
|
i2=i0+28*NSS
|
|
|
|
|
i3=i0+56*NSS
|
|
|
|
|
i4=i0+84*NSS
|
|
|
|
|
i5=i0+112*NSS
|
|
|
|
|
i6=i0+140*NSS
|
|
|
|
|
|
|
|
|
|
z1=0.
|
|
|
|
|
z2=0.
|
|
|
|
|
z3=0.
|
|
|
|
|
z4=0.
|
|
|
|
|
z5=0.
|
|
|
|
|
z6=0.
|
|
|
|
|
|
|
|
|
|
if(itwk.eq.1) then
|
|
|
|
|
dt=1/(12000.0/32.0)
|
|
|
|
|
dphi=twopi*f0*dt
|
|
|
|
|
phi=0.0
|
|
|
|
|
do i=1,4*NSS
|
|
|
|
|
ctwk(i)=cmplx(cos(phi),sin(phi))
|
|
|
|
|
phi=mod(phi+dphi,twopi)
|
|
|
|
|
enddo
|
|
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
if(itwk.eq.1) csync2=ctwk*csynca !Tweak the frequency
|
|
|
|
|
if(i1.ge.0 .and. i1+4*NSS-1.le.NP-1) then
|
|
|
|
|
z1=sum(cd0(i1:i1+4*NSS-1)*conjg(csync2))
|
|
|
|
|
elseif( i1.lt.0 ) then
|
|
|
|
|
npts=(i1+4*NSS-1)/2
|
|
|
|
|
if(npts.le.40) then
|
|
|
|
|
z1=0.
|
|
|
|
|
else
|
|
|
|
|
z1=sum(cd0(0:i1+4*NSS-1)*conjg(csync2(4*NSS-npts:)))
|
|
|
|
|
endif
|
|
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
if(itwk.eq.1) csync2=ctwk*csyncb !Tweak the frequency
|
|
|
|
|
if(i2.ge.0 .and. i2+4*NSS-1.le.NP-1) then
|
|
|
|
|
z2=sum(cd0(i2:i2+4*NSS-1)*conjg(csync2))
|
|
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
if(itwk.eq.1) csync2=ctwk*csyncc !Tweak the frequency
|
|
|
|
|
if(i3.ge.0 .and. i3+4*NSS-1.le.NP-1) then
|
|
|
|
|
z3=sum(cd0(i3:i3+4*NSS-1)*conjg(csync2))
|
|
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
if(itwk.eq.1) csync2=ctwk*csyncd !Tweak the frequency
|
|
|
|
|
if(i4.ge.0 .and. i4+4*NSS-1.le.NP-1) then
|
|
|
|
|
z4=sum(cd0(i4:i4+4*NSS-1)*conjg(csync2))
|
|
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
if(itwk.eq.1) csync2=ctwk*csynce !Tweak the frequency
|
|
|
|
|
if(i5.ge.0 .and. i5+4*NSS-1.le.NP-1) then
|
|
|
|
|
z5=sum(cd0(i5:i5+4*NSS-1)*conjg(csync2))
|
|
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
if(itwk.eq.1) csync2=ctwk*csyncf !Tweak the frequency
|
|
|
|
|
if(i6.ge.0 .and. i6+4*NSS-1.le.NP-1) then
|
|
|
|
|
z6=sum(cd0(i6:i6+4*NSS-1)*conjg(csync2))
|
|
|
|
|
elseif( i6+4*NSS-1.gt.NP-1 ) then
|
|
|
|
|
npts=(NP-1-i6+1)
|
|
|
|
|
if(npts.le.40) then
|
|
|
|
|
z6=0.
|
|
|
|
|
else
|
|
|
|
|
z6=sum(cd0(i6:i6+npts-1)*conjg(csync2(1:npts)))
|
|
|
|
|
endif
|
|
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
sync = p(z1) + p(z2) + p(z3) + p(z4) + p(z5) + p(z6)
|
|
|
|
|
|
|
|
|
|
return
|
|
|
|
|
end subroutine coherent_sync_ft4s
|
|
|
|
|
|
2020-04-28 07:21:13 -05:00
|
|
|
subroutine downsample_ft4s(ci,f0,hmod,co)
|
2020-04-26 14:34:09 -05:00
|
|
|
parameter(NI=144*300,NH=NI/2,NO=NI/15) ! downsample from 315 samples per symbol to 20
|
|
|
|
|
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)
|
2020-04-28 07:21:13 -05:00
|
|
|
b=16.0*hmod
|
2020-04-26 14:34:09 -05:00
|
|
|
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 downsample_ft4s
|
|
|
|
|
|
2020-04-28 07:21:13 -05:00
|
|
|
subroutine getcandidate_ft4s(c,npts,hmod,fs,fa,fb,ncand,candidates)
|
2020-04-26 14:34:09 -05:00
|
|
|
parameter(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
|
2020-04-28 07:21:13 -05:00
|
|
|
csfil(i)=exp(-((i-NH2)/(hmod*28.0))**2) ! revisit this
|
2020-04-26 14:34:09 -05:00
|
|
|
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)
|
2020-04-28 07:21:13 -05:00
|
|
|
candidates(ncand,2)=10*log10(bigspec(i)-1)-26.5
|
2020-04-26 14:34:09 -05:00
|
|
|
endif
|
|
|
|
|
enddo
|
|
|
|
|
return
|
|
|
|
|
end subroutine getcandidate_ft4s
|
|
|
|
|
|
|
|
|
|
subroutine ft4s_downsample(iwave,c)
|
|
|
|
|
|
|
|
|
|
! Input: i*2 data in iwave() at sample rate 12000 Hz
|
|
|
|
|
! Output: Complex data in c(), sampled at 375 Hz
|
|
|
|
|
|
|
|
|
|
include 'ft4s_params.f90'
|
|
|
|
|
parameter (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 ft4s_downsample
|
|
|
|
|
|
