WSJT-X/lib/ft8/ft8code.f90

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3.3 KiB
Fortran
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program ft8code
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! Provides examples of message packing, LDPC(174,91) encoding, bit and
! symbol ordering, and other details of the FT8 protocol.
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use packjt77
include 'ft8_params.f90' !Set various constants
include 'ft8_testmsg.f90'
parameter (NWAVE=NN*NSPS)
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character*37 msg,msgsent
character*9 comment
character bad*1,msgtype*18
integer itone(NN)
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integer*1 msgbits(77),codeword(174)
logical short
! Get command-line argument(s)
nargs=iargc()
if(nargs.ne.1 .and. nargs.ne.3) then
print*
print*,'Program ft8code: Provides examples of message packing, ', &
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'LDPC(174,91) encoding,'
print*,'bit and symbol ordering, and other details of the FT8 protocol.'
print*
print*,'Usage: ft8code [-c grid] "message" # Results for specified message'
print*,' ft8code -T # Examples of all message types'
print*,' ft8code -t # Short format examples'
go to 999
endif
call getarg(1,msg) !Message to be transmitted
short=.false.
if(len(trim(msg)).eq.2 .and. (msg(1:2).eq.'-T' .or. msg(1:2).eq.'-t')) then
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nmsg=NTEST
short=msg(1:2).eq.'-t'
else
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call fmtmsg(msg,iz) !To upper case; collapse multiple blanks
nmsg=1
endif
if(.not.short) write(*,1010)
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1010 format(4x,'Message',31x,'Decoded',29x,'Err i3.n3'/100('-'))
do imsg=1,nmsg
if(nmsg.gt.1) msg=testmsg(imsg)
! Generate msgsent, msgbits, and itone
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i3=-1
n3=-1
call genft8(msg,i3,n3,msgsent,msgbits,itone)
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call encode174_91(msgbits,codeword)
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msgtype=""
if(i3.eq.0) then
if(n3.eq.0) msgtype="Free text"
if(n3.eq.1) msgtype="DXpedition mode"
if(n3.eq.2) msgtype="EU VHF Contest"
if(n3.eq.3) msgtype="ARRL Field Day"
if(n3.eq.4) msgtype="ARRL Field Day"
if(n3.eq.5) msgtype="Telemetry"
if(n3.ge.6) msgtype="Undefined type"
endif
if(i3.eq.1) msgtype="Standard msg"
if(i3.eq.2) msgtype="EU VHF Contest"
if(i3.eq.3) msgtype="ARRL RTTY Roundup"
if(i3.eq.4) msgtype="Nonstandard call"
if(i3.ge.5) msgtype="Undefined type"
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if(i3.ge.1) n3=-1
bad=" "
comment=' '
if(msg.ne.msgsent) bad="*"
if(short) then
if(n3.ge.0) then
write(*,1020) i3,n3,msg,bad,msgtype
1020 format(i1,'.',i1,2x,a37,1x,a1,1x,a18)
else
write(*,1022) i3,msg,bad,msgtype
1022 format(i1,'.',3x,a37,1x,a1,1x,a18)
endif
else
if(n3.ge.0) then
write(*,1024) imsg,msg,msgsent,bad,i3,n3,msgtype,comment
1024 format(i2,'.',1x,a37,1x,a37,1x,a1,2x,i1,'.',i1,1x,a18,1x,a9)
else
write(*,1026) imsg,msg,msgsent,bad,i3,msgtype,comment
1026 format(i2,'.',1x,a37,1x,a37,1x,a1,2x,i1,'.',1x,1x,a18,1x,a9)
endif
endif
enddo
if(nmsg.eq.1) then
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write(*,1030) msgbits
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1030 format(/'Source-encoded message, 77 bits: ',/77i1)
write(*,1031) codeword(78:91)
1031 format(/'14-bit CRC: ',/14i1)
write(*,1032) codeword(92:174)
1032 format(/'83 Parity bits: ',/83i1)
write(*,1034) itone
1034 format(/'Channel symbols (79 tones):'/ &
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' Sync ',14x,'Data',15x,'Sync',15x,'Data',15x,'Sync'/ &
7i1,1x,29i1,1x,7i1,1x,29i1,1x,7i1)
endif
999 end program ft8code