From 44d2f446a27f7e716a05a031dd3a584ed6450921 Mon Sep 17 00:00:00 2001
From: Joe Taylor <k1jt@arrl.org>
Date: Thu, 21 Jul 2016 20:30:04 +0000
Subject: [PATCH] Test program for improved sync detection.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6936 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
---
 lib/qra/qra64/qra64sim.f90 |   1 -
 lib/qra64a.f90             |   4 +-
 lib/qratest.f90            | 116 +++++++++++++++++++++++++++++++++++++
 3 files changed, 119 insertions(+), 2 deletions(-)
 create mode 100644 lib/qratest.f90

diff --git a/lib/qra/qra64/qra64sim.f90 b/lib/qra/qra64/qra64sim.f90
index 9da534117..43d90e7d1 100644
--- a/lib/qra/qra64/qra64sim.f90
+++ b/lib/qra/qra64/qra64sim.f90
@@ -76,7 +76,6 @@ program qra64sim
 
         bandwidth_ratio=2500.0/6000.0
         sig=sqrt(2*bandwidth_ratio)*10.0**(0.05*xsnr)
-!        sig=sqrt(2.0)*10.0**(0.05*xsnr)
         if(xsnr.gt.90.0) sig=1.0
         write(*,1020) ifile,isig,f0,csubmode,xsnr,xdt,fspread,msg
 1020    format(i4,i4,f10.3,2x,a1,2x,f5.1,f6.2,f5.1,1x,a22)
diff --git a/lib/qra64a.f90 b/lib/qra64a.f90
index 3da2e57d0..fbe60780e 100644
--- a/lib/qra64a.f90
+++ b/lib/qra64a.f90
@@ -2,7 +2,7 @@ subroutine qra64a(dd0,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12,   &
      hisgrid_6,sync,nsnr,dtx,nfreq,decoded,nft)
 
   use packjt
-  parameter (NFFT=2*6912,NH=NFFT/2,NZ=5760,NMAX=60*12000)
+  parameter (NFFT=2*6912,NZ=5760,NMAX=60*12000)
   character decoded*22
   character*12 mycall_12,hiscall_12
   character*6 mycall,hiscall,hisgrid_6
@@ -21,6 +21,8 @@ subroutine qra64a(dd0,nutc,nf1,nf2,nfqso,ntol,mycall_12,hiscall_12,   &
   common/qra64com/ss(NZ,194),s3(0:63,1:63),ccf(NZ,0:25)
   save
 
+!  write(60) dd0
+
   decoded='                      '
   nft=99
   nsnr=-30
diff --git a/lib/qratest.f90 b/lib/qratest.f90
new file mode 100644
index 000000000..400264bc4
--- /dev/null
+++ b/lib/qratest.f90
@@ -0,0 +1,116 @@
+program qratest
+
+  parameter (NMAX=60*12000) 
+  real dd(NMAX)
+
+  do n=1,999
+     read(60,end=999) dd
+     call sync64(dd,dtx,f0,snr)
+     write(*,1000) dtx,f0,snr
+1000 format('DT:',f6.2,'   f0:',f7.1,'   Sync S/N:',f10.1)
+  enddo
+
+999 end program qratest
+
+subroutine sync64(dd,dtx,f0,snr)
+  parameter (NMAX=60*12000)
+  real dd(NMAX)
+  real x(672000)
+
+  real s0(0:16127)
+  real s1(0:16127)
+  real s2(0:16127)
+  real s3(0:16127)
+
+  real s0a(0:16127)
+  real s1a(0:16127)
+  real s2a(0:16127)
+  real s3a(0:16127)
+
+  integer icos7(0:6)
+  integer ipk(1)
+
+  complex cc(0:16127)
+  complex c0(0:336000)
+  complex c1(0:16127)
+  complex c2(0:16127)
+  complex c3(0:16127)
+  equivalence (x,c0)
+  data icos7/2,5,6,0,4,1,3/                            !Costas 7x7 pattern
+
+  twopi=8.0*atan(1.0)
+  dfgen=12000.0/6912.0
+  k=-1
+  phi=0.
+  do j=0,6
+     dphi=twopi*icos7(j)*dfgen/4000.0
+     do i=1,2304
+        phi=phi + dphi
+        if(phi.gt.twopi) phi=phi-twopi
+        k=k+1
+        cc(k)=cmplx(cos(phi),sin(phi))
+     enddo
+  enddo
+
+  npts0=54*12000
+  nfft1=672000
+  nfft2=nfft1/3
+  df1=12000.0/nfft1
+  fac=2.0/nfft1
+  x=fac*dd(1:nfft1)
+  call four2a(c0,nfft1,1,-1,0)               !Forward r2c FFT
+
+  call four2a(c0,nfft2,1,1,1)                !Inverse c2c FFT
+  npts2=npts0/3                              !Downsampled complex data length
+  nfft3=16128
+  nh3=nfft3/2
+  df3=4000.0/nfft3
+  iz=750.0/df3
+  smax=0.
+  jpk=0
+  do j1=0,24000,20
+     j2=j1 + 39*2304
+     j3=j1 + 77*2304
+     c1=1.e-4*c0(j1:j1+16127) * conjg(cc)
+     call four2a(c1,nfft3,1,-1,1)
+     c2=1.e-4*c0(j2:j2+16127) * conjg(cc)
+     call four2a(c2,nfft3,1,-1,1)
+     c3=1.e-4*c0(j3:j3+16127) * conjg(cc)
+     call four2a(c3,nfft3,1,-1,1)
+     do i=0,nfft3-1
+        freq=i*df3
+        s1(i)=real(c1(i))**2 + aimag(c1(i))**2
+        s2(i)=real(c2(i))**2 + aimag(c2(i))**2
+        s3(i)=real(c3(i))**2 + aimag(c3(i))**2
+     enddo
+     call smo121(s1,nfft3)
+     call smo121(s2,nfft3)
+     call smo121(s3,nfft3)
+     s0=s1+s2+s3
+     s=maxval(s0)
+     if(s.gt.smax) then
+        jpk=j1
+        s0a=s0
+        s1a=s1
+        s2a=s2
+        s3a=s3
+        smax=s
+        ipk=maxloc(s0)
+        dtx=jpk/4000.0 - 1.0
+        f0=(ipk(1)-1)*df3
+     endif
+  enddo
+
+  sq=dot_product(s0a,s0a)
+  ave=sum(s0a)/nfft3
+  rms=sqrt(sq/nfft3 - ave*ave)
+  snr=(smax-ave)/rms
+
+  do i=0,nfft3-1
+     freq=i*df3
+     if(freq.gt.2500.0) exit
+     write(14,1020) freq,s0a(i),s1a(i),s2a(i),s3a(i)
+1020 format(f10.3,4f12.1)
+  enddo
+        
+end subroutine sync64