From badc63977706187c944bfed6de0cf69e1f7666f4 Mon Sep 17 00:00:00 2001
From: Steve Franke <s.j.franke@icloud.com>
Date: Wed, 6 Jun 2018 10:59:49 -0500
Subject: [PATCH] Fix a bug in sync8d.f90. Switching between Costas arrays
 should work now.

---
 lib/ft8/sync8d.f90 | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/lib/ft8/sync8d.f90 b/lib/ft8/sync8d.f90
index 6fd86a50f..708a8e8a5 100644
--- a/lib/ft8/sync8d.f90
+++ b/lib/ft8/sync8d.f90
@@ -1,19 +1,20 @@
 subroutine sync8d(cd0,i0,ctwk,itwk,itype,sync)
 
 ! Compute sync power for a complex, downsampled FT8 signal.
+! itype specifies which Costas array to use
 
   parameter(NP2=2812,NDOWN=60)
   complex cd0(3125)
-  complex csync(0:6,32)
+  complex csync(0:6,32),csync_1(0:6,32),csync_2(0:6,32)
   complex csync2(32)
   complex ctwk(32)
   complex z1,z2,z3
   logical first
-  integer icos7_1(0:6),icos7_2(0:6),icos7(0:6)
+  integer icos7_1(0:6),icos7_2(0:6)
   data icos7_1/2,5,6,0,4,1,3/
   data icos7_2/3,1,4,0,6,5,2/
   data first/.true./
-  save first,twopi,fs2,dt2,taus,baud,csync
+  save first,twopi,fs2,dt2,taus,baud,csync_1,csync_2
 
   p(z1)=real(z1)**2 + aimag(z1)**2          !Statement function for power
 
@@ -25,28 +26,30 @@ subroutine sync8d(cd0,i0,ctwk,itwk,itype,sync)
     taus=32*dt2                             !Symbol duration
     baud=1.0/taus                           !Keying rate
     do i=0,6
-      phi=0.0
-      dphi=twopi*icos7(i)*baud*dt2  
+      phi1=0.0
+      phi2=0.0
+      dphi1=twopi*icos7_1(i)*baud*dt2  
+      dphi2=twopi*icos7_2(i)*baud*dt2  
       do j=1,32
-        csync(i,j)=cmplx(cos(phi),sin(phi)) !Waveform for 7x7 Costas array
-        phi=mod(phi+dphi,twopi)
+        csync_1(i,j)=cmplx(cos(phi1),sin(phi1)) !Waveform for 7x7 Costas array
+        csync_2(i,j)=cmplx(cos(phi2),sin(phi2)) !Waveform for 7x7 Costas array
+        phi1=mod(phi1+dphi1,twopi)
+        phi2=mod(phi2+dphi2,twopi)
       enddo
     enddo
     first=.false.
   endif
 
-  if(itype.eq.1) then
-    icos7=icos7_1
-  else
-    icos7=icos7_2
-  endif
-
   sync=0
   do i=0,6                              !Sum over 7 Costas frequencies and
      i1=i0+i*32                         !three Costas arrays
      i2=i1+36*32
      i3=i1+72*32
-     csync2=csync(i,1:32)
+     if(itype.eq.1) then
+        csync2=csync_1(i,1:32)
+     else
+        csync2=csync_2(i,1:32)
+     endif
      if(itwk.eq.1) csync2=ctwk*csync2      !Tweak the frequency
      z1=0.
      z2=0.