WSJT-X/lib/ft4/ft4code.f90
2019-12-18 10:42:08 -05:00

102 lines
3.5 KiB
Fortran

program ft4code
! Provides examples of message packing, LDPC(174,91) encoding, bit and
! symbol ordering, and other details of the FT8 protocol.
use packjt77
include 'ft4_params.f90' !Set various constants
include 'ft4_testmsg.f90'
parameter (NWAVE=NN*NSPS)
character*37 msg,msgsent
character*77 c77
character*9 comment
character bad*1,msgtype*18
integer itone(NN)
integer*1 msgbits(77),rvec(77),codeword(174)
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, &
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, &
0,1,0,1,0,1,1,0,1,1,1,1,1,0,0,0,1,0,1/
! Get command-line argument(s)
nargs=iargc()
if(nargs.ne.1 .and. nargs.ne.3) then
print*
print*,'Program ft4code: Provides examples of message packing, ', &
'LDPC(174,91) encoding,'
print*,'bit and symbol ordering, and other details of the FT4 protocol.'
print*
print*,'Usage: ft4code [-c grid] "message" # Results for specified message'
print*,' ft4code -t # Examples of all message types'
go to 999
endif
call getarg(1,msg) !Message to be transmitted
if(len(trim(msg)).eq.2 .and. msg(1:2).eq.'-t') then
nmsg=NTEST
else
call fmtmsg(msg,iz) !To upper case; collapse multiple blanks
nmsg=1
endif
write(*,1010)
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
i3=-1
n3=-1
call pack77(msg,i3,n3,c77)
call genft4(msg,0,msgsent,msgbits,itone)
call encode174_91(msgbits,codeword)
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 calls"
if(i3.ge.5) msgtype="Undefined msg type"
if(i3.ge.1) n3=-1
bad=" "
comment=' '
if(msg.ne.msgsent) bad="*"
if(n3.ge.0) then
write(*,1020) imsg,msg,msgsent,bad,i3,n3,msgtype,comment
1020 format(i2,'.',1x,a37,1x,a37,1x,a1,2x,i1,'.',i1,1x,a18,1x,a9)
else
write(*,1022) imsg,msg,msgsent,bad,i3,msgtype,comment
1022 format(i2,'.',1x,a37,1x,a37,1x,a1,2x,i1,'.',1x,1x,a18,1x,a9)
endif
enddo
if(nmsg.eq.1) then
write(*,1030) ieor(msgbits,rvec)
1030 format(/'Source-encoded message before scrambling, 77 bits: ',/77i1)
write(*,1032) rvec
1032 format(/'Scrambling vector, 77 bits: ',/77i1)
write(*,1034) msgbits
1034 format(/'Source-encoded message after scrambling, 77 bits:'/77i1)
write(*,1036) codeword(78:91)
1036 format(/'14-bit CRC: ',/14i1)
write(*,1038) codeword(92:174)
1038 format(/'83 Parity bits: ',/83i1)
write(*,1040) 0,itone,0
1040 format(/'Channel symbols (105 tones):'/ &
'R Sync',13x,'Data',13x, &
' Sync',13x,'Data',13x, &
' Sync',13x,'Data',13x,' Sync R'/ &
i1,1x,4i1,1x,29i1,1x,4i1,1x,29i1,1x,4i1,1x,29i1,1x,4i1,i2)
endif
999 end program ft4code