From c5a0de621016ccf1d04770aefab3b35f1a7174d2 Mon Sep 17 00:00:00 2001
From: Joe Taylor <joe@princeton.edu>
Date: Wed, 23 Dec 2020 09:47:11 -0500
Subject: [PATCH] Partial implementation of Q65 message averaging.
---
lib/q65_decode.f90 | 2 +-
lib/q65_sync.f90 | 36 ++++++++++++++++++++++++++++++++----
lib/test_q65.f90 | 4 ++++
3 files changed, 37 insertions(+), 5 deletions(-)
diff --git a/lib/q65_decode.f90 b/lib/q65_decode.f90
index 7df4185f0..17557cd39 100644
--- a/lib/q65_decode.f90
+++ b/lib/q65_decode.f90
@@ -96,7 +96,7 @@ contains
call q65_sync(nutc,iwave,ntrperiod*12000,mode65,codewords,ncw,nsps, &
nfqso,ntol,emedelay,xdt,f0,snr1,width,dat4,snr2,id1)
call timer('sync_q65',1)
- if(id1.eq.1) then
+ if(id1.eq.1 .or. id1.ge.12) then
xdt1=xdt
f1=f0
go to 100
diff --git a/lib/q65_sync.f90 b/lib/q65_sync.f90
index 834059fa1..741436b55 100644
--- a/lib/q65_sync.f90
+++ b/lib/q65_sync.f90
@@ -24,17 +24,19 @@ subroutine q65_sync(nutc,iwave,nmax,mode_q65,codewords,ncw,nsps,nfqso,ntol, &
integer dat4(13)
integer ijpk(2)
logical unpk77_success
+ logical lavg
character*77 c77,decoded*37
real, allocatable :: s1(:,:) !Symbol spectra, 1/8-symbol steps
real, allocatable :: s3(:,:) !Data-symbol energies s3(LL,63)
+ real, allocatable,save :: s3avg(:,:) !Averaged data-symbol energies
real, allocatable :: ccf(:,:) !CCF(freq,lag)
real, allocatable :: ccf1(:) !CCF(freq) at best lag
real s3prob(0:63,63) !Symbol-value probabilities
real sync(85) !sync vector
complex, allocatable :: c0(:) !Complex spectrum of symbol
data isync/1,9,12,13,15,22,23,26,27,33,35,38,46,50,55,60,62,66,69,74,76,85/
- data sync(1)/99.0/
- save sync
+ data sync(1)/99.0/,LL0/-1/
+ save sync,navg,LL0
snr1=0.
id1=0
@@ -54,6 +56,12 @@ subroutine q65_sync(nutc,iwave,nmax,mode_q65,codewords,ncw,nsps,nfqso,ntol, &
allocate(s1(iz,jz))
allocate(s3(-64:LL-65,63))
+ if(LL.ne.LL0) then
+ if(allocated(s3avg)) deallocate(s3avg)
+ allocate(s3avg(-64:LL-65,63))
+ navg=0
+ LL0=LL
+ endif
allocate(c0(0:nfft-1))
allocate(ccf(-ia2:ia2,-53:214))
allocate(ccf1(-ia2:ia2))
@@ -63,6 +71,8 @@ subroutine q65_sync(nutc,iwave,nmax,mode_q65,codewords,ncw,nsps,nfqso,ntol, &
do k=1,22
sync(isync(k))=1.0 !Sync tone ON
enddo
+ s3avg=0.
+ navg=0
endif
fac=1/32767.0
@@ -175,7 +185,9 @@ subroutine q65_sync(nutc,iwave,nmax,mode_q65,codewords,ncw,nsps,nfqso,ntol, &
baud=12000.0/nsps
ibwa=1.8*log(baud*mode_q65) + 2
ibwb=min(10,ibwa+4)
- do ibw=ibwa,ibwb
+ lavg=.false.
+
+10 do ibw=ibwa,ibwb
b90=1.72**ibw
call q65_intrinsics_ff(s3,nsubmode,b90/baud,nFadingModel,s3prob)
call q65_dec_fullaplist(s3,s3prob,codewords,ncw,esnodb,dat4,plog,irc)
@@ -196,9 +208,9 @@ subroutine q65_sync(nutc,iwave,nmax,mode_q65,codewords,ncw,nsps,nfqso,ntol, &
smax=maxval(ccf1)
if(smax.gt.10.0) ccf1=10.0*ccf1/smax
go to 200
-! go to 900
endif
enddo
+ if(lavg) go to 900
!######################################################################
! Establish xdt, f0, and snr1 using sync symbols (and perhaps some AP symbols)
@@ -241,6 +253,7 @@ subroutine q65_sync(nutc,iwave,nmax,mode_q65,codewords,ncw,nsps,nfqso,ntol, &
if(snr1.gt.10.0) ccf1=(10.0/snr1)*ccf1
200 smax=maxval(ccf1)
+ if(lavg) id1=10+navg !This is an average decode
i1=-9999
i2=-9999
do i=-ia,ia
@@ -254,6 +267,21 @@ subroutine q65_sync(nutc,iwave,nmax,mode_q65,codewords,ncw,nsps,nfqso,ntol, &
enddo
close(17)
width=df*(i2-i1)
+ if(id1.ge.1) then
+ navg=0
+ s3avg=0.
+ if(lavg) go to 900
+ elseif(snr1.ge.0.0) then
+ s3avg=s3avg+s3
+ navg=navg+1
+ write(71,3071) nutc,navg,xdt,f0,snr1
+3071 format(2i5,3f10.2)
+ if(navg.ge.2) then
+ s3=s3avg/navg
+ lavg=.true.
+ go to 10
+ endif
+ endif
900 return
end subroutine q65_sync
diff --git a/lib/test_q65.f90 b/lib/test_q65.f90
index f614d2703..49a17c678 100644
--- a/lib/test_q65.f90
+++ b/lib/test_q65.f90
@@ -139,6 +139,10 @@ program test_q65
if(ntrperiod.le.30) i0=25
if(line(i0:i0).ne.' ') read(line(60:),*) idec
if(idec.lt.0) cycle
+ if(idec.ge.12) then
+ iavg=idec-10
+ idec=1
+ endif
if(decok) then
ndecn=ndecn + 1
if(iavg.le.1) ndec1=ndec1 + 1