mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-01 08:07:10 -04:00
59295f14ed
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6454 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
121 lines
3.4 KiB
Fortran
121 lines
3.4 KiB
Fortran
program JTMSKfer
|
|
|
|
! Measure the frame error rate (fer) of the rate 1/2, K=13 conv. code with
|
|
! coherent BPSK, Viterbi decoding, perfect sync. The results are to be
|
|
! compared with LDPC fer's produced by the routines in the ldpc sandbox folder.
|
|
! These coherent BPSK results will not correspond to JTMSK.
|
|
|
|
use iso_c_binding, only: c_loc,c_size_t
|
|
use hashing
|
|
use packjt
|
|
character msg*22,decoded*22
|
|
integer*4 i4tone(234) !Channel symbols (values 0-1)
|
|
integer*1 e1(201)
|
|
integer*4 r1(201)
|
|
real rd(201), tmp
|
|
integer*1, target :: d8(13)
|
|
integer mettab(0:255,0:1) !Metric table for BPSK modulation
|
|
integer*1 i1hash(4)
|
|
integer*4 i4Msg6BitWords(12) !72-bit message as 6-bit words
|
|
character*72 c72
|
|
real xp(29)
|
|
equivalence (ihash,i1hash)
|
|
data xp/0.500000, 0.401241, 0.309897, 0.231832, 0.168095, &
|
|
0.119704, 0.083523, 0.057387, 0.039215, 0.026890, &
|
|
0.018084, 0.012184, 0.008196, 0.005475, 0.003808, &
|
|
0.002481, 0.001710, 0.001052, 0.000789, 0.000469, &
|
|
0.000329, 0.000225, 0.000187, 0.000086, 0.000063, &
|
|
0.000017, 0.000091, 0.000032, 0.000045/
|
|
|
|
nmsg=1
|
|
|
|
! Get the metric table
|
|
bias=0.0
|
|
scale=20.0
|
|
xln2=log(2.0)
|
|
mettab=0
|
|
do i=128,156
|
|
x0=log(max(0.001,2.0*xp(i-127)))/xln2
|
|
x1=log(max(0.001,2.0*(1-xp(i-127))))/xln2
|
|
mettab(i,0)=nint(scale*(x0-bias))
|
|
mettab(i,1)=nint(scale*(x1-bias))
|
|
mettab(256-i,0)=mettab(i,1)
|
|
mettab(256-i,1)=mettab(i,0)
|
|
enddo
|
|
do i=157,255
|
|
mettab(i,0)=mettab(156,0)
|
|
mettab(i,1)=mettab(156,1)
|
|
mettab(256-i,0)=mettab(i,1)
|
|
mettab(256-i,1)=mettab(i,0)
|
|
enddo
|
|
|
|
rdscale=2.0
|
|
ntrials=1000000
|
|
rate=72.0/198.0
|
|
msg="123"
|
|
call fmtmsg(msg,iz) !To upper case, collapse multiple blanks
|
|
ichk=0
|
|
call genmsk(msg,ichk,decoded,i4tone,itype) !Encode message into tone #s
|
|
|
|
! Extract the data symbols, skipping over sync and parity bits
|
|
n1=35
|
|
n2=69
|
|
n3=94
|
|
|
|
r1(1:n1)=i4tone(11+1:11+n1)
|
|
r1(n1+1:n1+n2)=i4tone(23+n1+1:23+n1+n2)
|
|
r1(n1+n2+1:n1+n2+n3)=i4tone(35+n1+n2+1:35+n1+n2+n3)
|
|
|
|
! call sgran()
|
|
|
|
do idb=6,11
|
|
db=idb/2.0-0.5 ! Eb/N0=1/(2*R*sigma^2), so sigma= sqrt( 1/(2*R*Eb/N0) )
|
|
sigma=1/sqrt( 2*rate*(10**(db/10.0)) )
|
|
|
|
ngood=0 ! decoded = msg
|
|
ngoodhash=0 ! will include undetected errors plus actual good ones
|
|
|
|
do itrial=1,ntrials
|
|
do i=1,n1+n2+n3
|
|
tmp=( 2.0 * ( r1(i)-0.5 ) + sigma*gran() )*rdscale
|
|
if( tmp .lt. 0 ) then
|
|
rd(i)=min(127.0,-tmp)
|
|
elseif( tmp .gt.0 ) then
|
|
rd(i)=max(-tmp,-127.0)
|
|
endif
|
|
enddo
|
|
|
|
j=0
|
|
do i=1,99
|
|
j=j+1
|
|
e1(j)=rd(i)
|
|
j=j+1
|
|
e1(j)=rd(i+99)
|
|
enddo
|
|
|
|
nb1=87
|
|
call vit213(e1,nb1,mettab,d8,metric)
|
|
|
|
igoodhash=0
|
|
ihash=nhash(c_loc(d8),int(9,c_size_t),146)
|
|
ihash=2*iand(ihash,32767)
|
|
decoded=" "
|
|
if(d8(10).eq.i1hash(2) .and. d8(11).eq.i1hash(1)) then
|
|
igoodhash=1
|
|
write(c72,1012) d8(1:9)
|
|
1012 format(9b8.8)
|
|
read(c72,1014) i4Msg6BitWords
|
|
1014 format(12b6.6)
|
|
call unpackmsg(i4Msg6BitWords,decoded) !Unpack to get msgsent
|
|
endif
|
|
|
|
if( igoodhash .eq. 1) ngoodhash=ngoodhash+1
|
|
if( decoded .eq. msg ) ngood=ngood+1
|
|
|
|
enddo
|
|
|
|
write(*,1023) db,sigma,ntrials,ngood,ngoodhash-ngood
|
|
1023 format("db:",f6.2," sigma:",f6.2," ntot:",i8," good:",i8," undet:",i8)
|
|
enddo
|
|
end program JTMSKfer
|