subroutine genmsk_128_90(msg0,ichk,msgsent,i4tone,itype) ! s8 + 48bits + s8 + 80 bits = 144 bits (72ms message duration) ! ! Encode an MSK144 message ! Input: ! - msg0 requested message to be transmitted ! - ichk if ichk=1, return only msgsent ! if ichk.ge.10000, set imsg=ichk-10000 for short msg ! - msgsent message as it will be decoded ! - i4tone array of audio tone values, 0 or 1 ! - itype message type ! 1 = standard message "Call_1 Call_2 Grid/Rpt" ! 2 = type 1 prefix ! 3 = type 1 suffix ! 4 = type 2 prefix ! 5 = type 2 suffix ! 6 = free text (up to 13 characters) ! 7 = short message " Rpt" use iso_c_binding, only: c_loc,c_size_t use packjt77 character*37 msg0 character*37 message !Message to be generated character*37 msgsent !Message as it will be received character*77 c77 integer*4 i4tone(144) integer*1 codeword(128) integer*1 msgbits(77) integer*1 bitseq(144) !Tone #s, data and sync (values 0-1) integer*1 s8(8) real*8 pp(12) real*8 xi(864),xq(864),pi,twopi data s8/0,1,1,1,0,0,1,0/ equivalence (ihash,i1hash) logical first,unpk77_success data first/.true./ save if(first) then first=.false. nsym=128 pi=4.0*atan(1.0) twopi=8.*atan(1.0) do i=1,12 pp(i)=sin((i-1)*pi/12) enddo endif message(1:37)=' ' itype=1 if(msg0(1:1).eq.'@') then !Generate a fixed tone read(msg0(2:5),*,end=1,err=1) nfreq !at specified frequency go to 2 1 nfreq=1000 2 i4tone(1)=nfreq else message=msg0 do i=1, 37 if(ichar(message(i:i)).eq.0) then message(i:37)=' ' exit endif enddo do i=1,37 !Strip leading blanks if(message(1:1).ne.' ') exit message=message(i+1:) enddo if(message(1:1).eq.'<') then i2=index(message,'>') i1=0 if(i2.gt.0) i1=index(message(1:i2),' ') if(i1.gt.0) then call genmsk40(message,msgsent,ichk,i4tone,itype) if(itype.lt.0) go to 999 i4tone(41)=-40 go to 999 endif endif i3=-1 n3=-1 call pack77(message,i3,n3,c77) call unpack77(c77,msgsent,unpk77_success) !Unpack to get msgsent if(ichk.eq.1) go to 999 read(c77,"(77i1)") msgbits call encode_128_90(msgbits,codeword) !Create 144-bit channel vector: !8-bit sync word + 48 bits + 8-bit sync word + 80 bits bitseq=0 bitseq(1:8)=s8 bitseq(9:56)=codeword(1:48) bitseq(57:64)=s8 bitseq(65:144)=codeword(49:128) bitseq=2*bitseq-1 xq(1:6)=bitseq(1)*pp(7:12) !first bit is mapped to 1st half-symbol on q do i=1,71 is=(i-1)*12+7 xq(is:is+11)=bitseq(2*i+1)*pp enddo xq(864-5:864)=bitseq(1)*pp(1:6) !last half symbol do i=1,72 is=(i-1)*12+1 xi(is:is+11)=bitseq(2*i)*pp enddo ! Map I and Q to tones. i4tone=0 do i=1,72 i4tone(2*i-1)=(bitseq(2*i)*bitseq(2*i-1)+1)/2; i4tone(2*i)=-(bitseq(2*i)*bitseq(mod(2*i,144)+1)-1)/2; enddo endif ! Flip polarity i4tone=-i4tone+1 999 return end subroutine genmsk_128_90