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https://github.com/saitohirga/WSJT-X.git
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201 lines
6.5 KiB
Fortran
201 lines
6.5 KiB
Fortran
module q65_decode
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type :: q65_decoder
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procedure(q65_decode_callback), pointer :: callback
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contains
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procedure :: decode
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end type q65_decoder
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abstract interface
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subroutine q65_decode_callback (this,nutc,sync,nsnr,dt,freq, &
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decoded,nap,ntrperiod)
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import q65_decoder
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implicit none
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class(q65_decoder), intent(inout) :: this
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integer, intent(in) :: nutc
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real, intent(in) :: sync
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integer, intent(in) :: nsnr
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real, intent(in) :: dt
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real, intent(in) :: freq
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character(len=37), intent(in) :: decoded
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integer, intent(in) :: nap
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integer, intent(in) :: ntrperiod
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end subroutine q65_decode_callback
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end interface
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contains
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subroutine decode(this,callback,iwave,nutc,ntrperiod,nsubmode,nfqso, &
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ntol,ndepth,lclearave,emedelay,mycall,hiscall,hisgrid,nQSOprogress, &
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ncontest,lapcqonly)
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! Decodes Q65 signals
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! Input: iwave Raw data, i*2
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! nutc UTC for time-tagging the decode
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! ntrperiod T/R sequence length (s)
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! nsubmode Tone-spacing indicator, 0-4 for A-E
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! nfqso Target signal frequency (Hz)
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! ntol Search range around nfqso (Hz)
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! ndepth Optional decoding level
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! Output: sent to the callback routine for display to user
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use timer_module, only: timer
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use packjt77
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use, intrinsic :: iso_c_binding
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use q65 !Shared variables
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parameter (NMAX=300*12000) !Max TRperiod is 300 s
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class(q65_decoder), intent(inout) :: this
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procedure(q65_decode_callback) :: callback
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character(len=12) :: mycall, hiscall !Used for AP decoding
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character(len=6) :: hisgrid
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character*37 decoded !Decoded message
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character*77 c77
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character*78 c78
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integer*2 iwave(NMAX) !Raw data
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real, allocatable :: dd(:) !Raw data
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integer dat4(13) !Decoded message as 12 6-bit integers
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integer apmask1(78),apsymbols1(78)
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integer dgen(13)
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integer codewords(63,206)
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logical lclearave,lapcqonly,unpk77_success
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complex, allocatable :: c00(:) !Analytic signal, 6000 Sa/s
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complex, allocatable :: c0(:) !Analytic signal, 6000 Sa/s
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idec=-1
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mode65=2**nsubmode
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npts=ntrperiod*12000
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nfft1=ntrperiod*12000
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nfft2=ntrperiod*6000
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if(lclearave) nsave=0
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allocate(dd(npts))
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allocate (c00(0:nfft1-1))
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allocate (c0(0:nfft1-1))
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if(ntrperiod.eq.15) then
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nsps=1800
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else if(ntrperiod.eq.30) then
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nsps=3600
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else if(ntrperiod.eq.60) then
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nsps=7200
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else if(ntrperiod.eq.120) then
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nsps=16000
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else if(ntrperiod.eq.300) then
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nsps=41472
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else
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stop 'Invalid TR period'
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endif
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baud=12000.0/nsps
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df1=12000.0/nfft1
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this%callback => callback
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nFadingModel=1
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! Set up the codewords for full-AP list decoding
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call q65_set_list(mycall,hiscall,hisgrid,codewords,ncw)
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dgen=0
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call q65_enc(dgen,codewords) !Initialize the Q65 codec
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call timer('sync_q65',0)
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call q65_sync(nutc,iwave,ntrperiod,mode65,codewords,ncw,nsps, &
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nfqso,ntol,ndepth,lclearave,emedelay,xdt,f0,snr1,width,dat4, &
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snr2,idec)
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call timer('sync_q65',1)
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if(idec.ge.0) then
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xdt1=xdt !We have a list-decode result
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f1=f0
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go to 100
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endif
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if(snr1.lt.2.8) then
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xdt1=0. !No reliable sync, abandon decoding attempt
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f1=0.
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go to 100
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endif
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jpk0=(xdt+1.0)*6000 !Index of nominal start of signal
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if(ntrperiod.le.30) jpk0=(xdt+0.5)*6000 !For shortest sequences
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if(jpk0.lt.0) jpk0=0
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fac=1.0/32767.0
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dd=fac*iwave(1:npts)
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call ana64(dd,npts,c00) !Convert to complex c00() at 6000 Sa/s
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! Generate ap symbols as in FT8
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call ft8apset(mycall,hiscall,ncontest,apsym0,aph10)
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where(apsym0.eq.-1) apsym0=0
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! Main decoding loop starts here
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npasses=2
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if(nQSOprogress.eq.5) npasses=3
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if(lapcqonly) npasses=1
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iaptype=0
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do ipass=0,npasses
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apmask=0 !Try first with no AP information
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apsymbols=0
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if(ipass.ge.1) then
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! Subsequent passes use AP information appropiate for nQSOprogress
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call q65_ap(nQSOprogress,ipass,ncontest,lapcqonly,iaptype, &
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apsym0,apmask1,apsymbols1)
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write(c78,1050) apmask1
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1050 format(78i1)
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read(c78,1060) apmask
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1060 format(13b6.6)
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write(c78,1050) apsymbols1
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read(c78,1060) apsymbols
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if(iaptype.eq.4) then
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do j=1,3
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ng15=32401+j
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write(c78(60:74),'(b15.15)') ng15
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read(c78,1060) dgen
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call q65_enc(dgen,codewords(1,j))
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enddo
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endif
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endif
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call timer('q65loops',0)
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call q65_loops(c00,npts/2,nsps/2,mode65,nsubmode,ndepth,jpk0, &
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xdt,f0,iaptype,xdt1,f1,snr2,dat4,idec)
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call timer('q65loops',1)
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if(idec.gt.0) go to 100 !Successful decode, we're done
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enddo
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! There was no single-transmission decode.
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if(iand(ndepth,16).eq.16) then
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! Try for an average decode.
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call q65_avg2(ntrperiod,ntol,baud,nsubmode,nQSOprogress,lapcqonly, &
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ibwa,ibwb,codewords,ncw,xdt,f0,snr1,snr2,dat4,idec)
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endif
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100 decoded=' '
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if(idec.gt.0) then
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! ------------------------------------------------------
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! idec Meaning
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! ------------------------------------------------------
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! -1: No decode
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! 1: Decode with AP for "MyCall DxCall ?"
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! 2: Decode without AP information
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! 3: Decode with AP for "CQ ? ?"
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! 4: Decode with AP for "MyCall ? ?"
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! ------------------------------------------------------
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! Second digit (if any) is number of sequences averaged.
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! ------------------------------------------------------
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! Unpack decoded message for display to user
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write(c77,1000) dat4(1:12),dat4(13)/2
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1000 format(12b6.6,b5.5)
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call unpack77(c77,0,decoded,unpk77_success) !Unpack to get msgsent
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nsnr=nint(snr2)
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call this%callback(nutc,sync,nsnr,xdt1,f1,decoded,idec,ntrperiod)
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call q65_clravg
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else
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! Report sync, even if no decode.
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nsnr=db(snr1) - 35.0
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idec=-1
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call this%callback(nutc,sync,nsnr,xdt1,f1,decoded, &
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idec,ntrperiod)
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endif
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return
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end subroutine decode
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end module q65_decode
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