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110 lines
2.9 KiB
Fortran
110 lines
2.9 KiB
Fortran
subroutine ft8q3(cd,xdt,f0,call_1,call_2,grid4,msgbest,snr)
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! Get q3-style decodes for FT8.
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use packjt77
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parameter(NN=79,NSPS=32)
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parameter(NWAVE=NN*NSPS) !2528
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parameter(NZ=3200,NLAGS=NZ-NWAVE)
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character*12 call_1,call_2
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character*4 grid4
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character*37 msg,msgbest,msgsent
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character c77*77
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complex cwave(0:NWAVE-1)
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complex cd(0:NZ-1)
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complex z
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real xjunk(NWAVE)
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real ccf(0:NLAGS-1)
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real ccfmsg(206)
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integer itone(NN)
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integer*1 msgbits(77)
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logical std_1,std_2
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if(xdt.eq.-99.0) return !Silence compiler warning
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call stdcall(call_1,std_1)
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call stdcall(call_2,std_2)
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fs=200.0 !Sample rate (Hz)
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dt=1.0/fs !Sample interval (s)
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bt=2.0
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ccfbest=0.
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lagbest=-1
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do imsg=1,206
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msg=trim(call_1)//' '//trim(call_2)
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i=imsg
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if(.not.std_1) then
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if(i.eq.1 .or. i.ge.6) msg='<'//trim(call_1)//'> '//trim(call_2)
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if(i.ge.2 .and. i.le.4) msg=trim(call_1)//' <'//trim(call_2)//'>'
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else if(.not.std_2) then
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if(i.le.4 .or. i.eq.6) msg='<'//trim(call_1)//'> '//trim(call_2)
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if(i.ge.7) msg=trim(call_1)//' <'//trim(call_2)//'>'
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endif
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j0=len(trim(msg))+2
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if(i.eq.2) msg(j0:j0+2)='RRR'
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if(i.eq.3) msg(j0:j0+3)='RR73'
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if(i.eq.4) msg(j0:j0+1)='73'
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if(i.eq.5) then
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if(std_2) msg='CQ '//trim(call_2)//' '//grid4
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if(.not.std_2) msg='CQ '//trim(call_2)
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endif
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if(i.eq.6 .and. std_2) msg(j0:j0+3)=grid4
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if(i.ge.7 .and. i.le.206) then
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isnr = -50 + (i-7)/2
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if(iand(i,1).eq.1) then
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write(msg(j0:j0+2),'(i3.2)') isnr
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if(msg(j0:j0).eq.' ') msg(j0:j0)='+'
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else
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write(msg(j0:j0+3),'("R",i3.2)') isnr
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if(msg(j0+1:j0+1).eq.' ') msg(j0+1:j0+1)='+'
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endif
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endif
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! Source-encode, then get itone()
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i3=-1
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n3=-1
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call pack77(msg,i3,n3,c77)
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call genft8(msg,i3,n3,msgsent,msgbits,itone)
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! Generate complex cwave
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call gen_ft8wave(itone,NN,NSPS,bt,fs,f0,cwave,xjunk,1,NWAVE)
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lagmax=-1
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ccfmax=0.
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nsum=32*2
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do lag=0,nlags-1
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z=0.
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s=0.
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do i=0,NWAVE-1
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z=z + cd(i+lag)*conjg(cwave(i))
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if(mod(i,nsum).eq.nsum-1 .or. i.eq.NWAVE-1) then
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s=s + abs(z)
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z=0.
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endif
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enddo
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ccf(lag)=s
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if(ccf(lag).gt.ccfmax) then
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ccfmax=ccf(lag)
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lagmax=lag
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endif
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enddo ! lag
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ccfmsg(imsg)=ccfmax
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if(ccfmax.gt.ccfbest) then
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ccfbest=ccfmax
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lagbest=lagmax
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msgbest=msg
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endif
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enddo ! imsg
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call pctile(ccfmsg,207,50,base)
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call pctile(ccfmsg,207,67,sigma)
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sigma=sigma-base
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ccfmsg=(ccfmsg-base)/sigma
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! do imsg=1,207
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! write(44,3044) imsg,ccfmsg(imsg)
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!3044 format(i5,f10.3)
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! enddo
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snr=maxval(ccfmsg)
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return
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end subroutine ft8q3
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