2019-12-18 10:02:00 -05:00
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program ft4code
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! Provides examples of message packing, LDPC(174,91) encoding, bit and
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! symbol ordering, and other details of the FT8 protocol.
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use packjt77
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include 'ft4_params.f90' !Set various constants
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include 'ft4_testmsg.f90'
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parameter (NWAVE=NN*NSPS)
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character*37 msg,msgsent
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character*77 c77
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character*9 comment
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character bad*1,msgtype*18
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integer itone(NN)
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integer*1 msgbits(77),rvec(77),codeword(174)
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data rvec/0,1,0,0,1,0,1,0,0,1,0,1,1,1,1,0,1,0,0,0,1,0,0,1,1,0,1,1,0, &
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1,0,0,1,0,1,1,0,0,0,0,1,0,0,0,1,0,1,0,0,1,1,1,1,0,0,1,0,1, &
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0,1,0,1,0,1,1,0,1,1,1,1,1,0,0,0,1,0,1/
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! Get command-line argument(s)
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nargs=iargc()
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if(nargs.ne.1 .and. nargs.ne.3) then
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print*
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print*,'Program ft4code: Provides examples of message packing, ', &
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'LDPC(174,91) encoding,'
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print*,'bit and symbol ordering, and other details of the FT4 protocol.'
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print*
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print*,'Usage: ft4code [-c grid] "message" # Results for specified message'
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print*,' ft4code -t # Examples of all message types'
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go to 999
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endif
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call getarg(1,msg) !Message to be transmitted
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if(len(trim(msg)).eq.2 .and. msg(1:2).eq.'-t') then
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nmsg=NTEST
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else
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call fmtmsg(msg,iz) !To upper case; collapse multiple blanks
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nmsg=1
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endif
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write(*,1010)
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1010 format(4x,'Message',31x,'Decoded',29x,'Err i3.n3'/100('-'))
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do imsg=1,nmsg
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if(nmsg.gt.1) msg=testmsg(imsg)
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! Generate msgsent, msgbits, and 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 genft4(msg,0,msgsent,msgbits,itone)
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call encode174_91(msgbits,codeword)
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msgtype=""
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if(i3.eq.0) then
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if(n3.eq.0) msgtype="Free text"
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if(n3.eq.1) msgtype="DXpedition mode"
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if(n3.eq.2) msgtype="EU VHF Contest"
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if(n3.eq.3) msgtype="ARRL Field Day"
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if(n3.eq.4) msgtype="ARRL Field Day"
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if(n3.eq.5) msgtype="Telemetry"
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if(n3.ge.6) msgtype="Undefined type"
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endif
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if(i3.eq.1) msgtype="Standard msg"
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if(i3.eq.2) msgtype="EU VHF Contest"
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if(i3.eq.3) msgtype="ARRL RTTY Roundup"
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if(i3.eq.4) msgtype="Nonstandard calls"
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if(i3.ge.5) msgtype="Undefined msg type"
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if(i3.ge.1) n3=-1
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bad=" "
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comment=' '
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if(msg.ne.msgsent) bad="*"
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if(n3.ge.0) then
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write(*,1020) imsg,msg,msgsent,bad,i3,n3,msgtype,comment
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1020 format(i2,'.',1x,a37,1x,a37,1x,a1,2x,i1,'.',i1,1x,a18,1x,a9)
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else
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write(*,1022) imsg,msg,msgsent,bad,i3,msgtype,comment
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1022 format(i2,'.',1x,a37,1x,a37,1x,a1,2x,i1,'.',1x,1x,a18,1x,a9)
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endif
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enddo
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if(nmsg.eq.1) then
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write(*,1030) ieor(msgbits,rvec)
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2019-12-18 10:42:08 -05:00
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1030 format(/'Source-encoded message before scrambling, 77 bits: ',/77i1)
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write(*,1032) rvec
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1032 format(/'Scrambling vector, 77 bits: ',/77i1)
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write(*,1034) msgbits
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1034 format(/'Source-encoded message after scrambling, 77 bits:'/77i1)
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write(*,1036) codeword(78:91)
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1036 format(/'14-bit CRC: ',/14i1)
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write(*,1038) codeword(92:174)
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1038 format(/'83 Parity bits: ',/83i1)
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write(*,1040) 0,itone,0
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1040 format(/'Channel symbols (105 tones):'/ &
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2019-12-18 10:02:00 -05:00
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'R Sync',13x,'Data',13x, &
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' Sync',13x,'Data',13x, &
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' Sync',13x,'Data',13x,' Sync R'/ &
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i1,1x,4i1,1x,29i1,1x,4i1,1x,29i1,1x,4i1,1x,29i1,1x,4i1,i2)
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endif
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999 end program ft4code
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