mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-12-02 00:55:12 -05:00
57 lines
1.4 KiB
Fortran
57 lines
1.4 KiB
Fortran
|
subroutine encode4K25A(message,codeword)
|
||
|
|
! A (280,70) rate 1/4 tailbiting convolutional code using
|
||
|
|
! the "4K25A" polynomials from EbNaut website.
|
||
|
|
! Code is transparent, has constraint length 25, and has dmin=58
|
||
|
|
character*10 g1,g2,g3,g4
|
||
|
|
integer*1 codeword(280)
|
||
|
|
!integer*1 p1(25),p2(25),p3(25),p4(25)
|
||
|
|
integer*1 p1(16),p2(16),p3(16),p4(16)
|
||
|
|
integer*1 gg(100)
|
||
|
|
integer*1 gen(280,70)
|
||
|
|
integer*1 itmp(280)
|
||
|
|
integer*1 message(70)
|
||
|
|
logical first
|
||
|
|
data first/.true./
|
||
|
|
data g1/"106042635"/
|
||
|
|
data g2/"125445117"/
|
||
|
|
data g3/"152646773"/
|
||
|
|
data g4/"167561761"/
|
||
|
|
!data p1/1,0,0,0,1,1,0,0,0,0,1,0,0,0,1,0,1,1,0,0,1,1,1,0,1/
|
||
|
|
!data p2/1,0,1,0,1,0,1,1,0,0,1,0,0,1,0,1,0,0,1,0,0,1,1,1,1/
|
||
|
|
!data p3/1,1,0,1,0,1,0,1,1,0,1,0,0,1,1,0,1,1,1,1,1,1,0,1,1/
|
||
|
|
!data p4/1,1,1,0,1,1,1,1,0,1,1,1,0,0,0,1,1,1,1,1,1,0,0,0,1/
|
||
|
|
data p1/1,0,1,0,1,1,0,0,1,1,0,1,1,1,1,1/
|
||
|
|
data p2/1,0,1,1,0,1,0,0,1,1,1,1,1,0,0,1/
|
||
|
|
data p3/1,1,0,0,1,0,1,1,0,1,1,1,0,0,1,1/
|
||
|
|
data p4/1,1,1,0,1,1,0,1,1,1,1,0,0,1,0,1/
|
||
|
|
|
||
|
|
save first,gen
|
||
|
|
|
||
|
|
if( first ) then ! fill the generator matrix
|
||
|
|
gg=0
|
||
|
|
! gg(1:25)=p1
|
||
|
|
! gg(26:50)=p2
|
||
|
|
! gg(51:75)=p3
|
||
|
|
! gg(76:100)=p4
|
||
|
|
gg(1:16)=p1
|
||
|
|
gg(17:32)=p2
|
||
|
|
gg(33:48)=p3
|
||
|
|
gg(49:64)=p4
|
||
|
|
gen=0
|
||
|
|
! gen(1:100,1)=gg(1:100)
|
||
|
|
gen(1:64,1)=gg(1:64)
|
||
|
|
do i=2,70
|
||
|
|
gen(:,i)=cshift(gen(:,i-1),-4,1)
|
||
|
|
enddo
|
||
|
|
first=.false.
|
||
|
|
endif
|
||
|
|
|
||
|
|
codeword=0
|
||
|
|
do i=1,70
|
||
|
|
if(message(i).eq.1) codeword=codeword+gen(:,i)
|
||
|
|
enddo
|
||
|
|
codeword=mod(codeword,2)
|
||
|
|
|
||
|
|
return
|
||
|
|
end subroutine encode4K25A
|