From f9e209f399f7bdc9080534c6b62f0ccf252ea338 Mon Sep 17 00:00:00 2001
From: Pavel Demin <pavel-demin@outlook.com>
Date: Sat, 13 Oct 2018 21:45:41 +0200
Subject: [PATCH] add cshift to ft8_downsample and sync8

---
 ft8_downsample.f90 | 14 +++++---------
 sync8.f90          | 10 +++++-----
 2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/ft8_downsample.f90 b/ft8_downsample.f90
index e07a036..05c3f0b 100644
--- a/ft8_downsample.f90
+++ b/ft8_downsample.f90
@@ -16,21 +16,17 @@ subroutine ft8_downsample(dd,newdat,f0,c1)
 ! Data in dd have changed, recompute the long FFT
      x(1:NMAX)=dd
      x(NMAX+1:NFFT1)=0.                       !Zero-pad the x array
-     call four2a(cx,NFFT1,1,-1,1)             !c2c FFT to freq domain
+     call four2a(x,NFFT1,1,-1,1)              !c2c FFT to freq domain
+     x=cshift(x,NFFT1/2)
      newdat=.false.
   endif
 
-  if(f0.lt.2000.0) then
-    f=f0+2000.0
-  else
-    f=f0-2000.0
-  endif
   df=4000.0/NFFT1
   baud=4000.0/NSPS
-  i0=nint(f/df)
-  ft=f+8.0*baud
+  i0=nint(f0/df)
+  ft=f0+8.0*baud
   it=min(nint(ft/df),NFFT1)
-  fb=f-1.0*baud
+  fb=f0-1.0*baud
   ib=max(1,nint(fb/df))
   k=0
   c1=0.
diff --git a/sync8.f90 b/sync8.f90
index 3ad6ad8..f25de77 100644
--- a/sync8.f90
+++ b/sync8.f90
@@ -3,7 +3,7 @@ subroutine sync8(dd,nfa,nfb,syncmin,nfqso,s,candidate,ncand,sbase)
   include 'ft8_params.f90'
 ! Search over +/- 2.5s relative to 0.5s TX start time.
   parameter (JZ=62)
-  complex cx(NFFT1)
+  complex cx(0:NFFT1)
   real s(NFFT1,NHSYM)
   real savg(NFFT1)
   real sbase(NFFT1)
@@ -19,6 +19,7 @@ subroutine sync8(dd,nfa,nfb,syncmin,nfqso,s,candidate,ncand,sbase)
   integer icos7(0:6)
   data icos7/2,5,6,0,4,1,3/                   !Costas 7x7 tone pattern
   equivalence (x,cx)
+  save cx
 
 ! Compute symbol spectra, stepping by NSTEP steps.
   savg=0.
@@ -31,11 +32,10 @@ subroutine sync8(dd,nfa,nfb,syncmin,nfqso,s,candidate,ncand,sbase)
      x(1:NSPS)=fac*dd(ia:ib)
      x(NSPS+1:)=0.
      call four2a(x,NFFT1,1,-1,1)              !c2c FFT
-     do i=2,NH1
-        s(i-1,j)=real(cx(i+NH1))**2 + aimag(cx(i+NH1))**2
-        s(i-1+NH1,j)=real(cx(i))**2 + aimag(cx(i))**2
+     x=cshift(x,NFFT1/2)
+     do i=1,NFFT1
+        s(i,j)=real(cx(i))**2 + aimag(cx(i))**2
      enddo
-     s(NH1,j)=real(cx(1))**2 + aimag(cx(1))**2
      savg=savg + s(1:NFFT1,j)                 !Average spectrum
   enddo
   call baseline(savg,nfa,nfb,sbase)