From 7201e5baab7048cb0b08a5394266a0f7d3e48b3e Mon Sep 17 00:00:00 2001
From: Joe Taylor <joe@princeton.edu>
Date: Wed, 31 Jan 2024 16:38:22 -0500
Subject: [PATCH] Add a missing file.

---
 lib/superfox/sync_sf.f90 | 52 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 lib/superfox/sync_sf.f90

diff --git a/lib/superfox/sync_sf.f90 b/lib/superfox/sync_sf.f90
new file mode 100644
index 000000000..bfe9c6c8f
--- /dev/null
+++ b/lib/superfox/sync_sf.f90
@@ -0,0 +1,52 @@
+subroutine sync_sf(crcvd,clo,f,t)
+
+  include "sfox_params.f90"
+  parameter (MMAX=150,JMAX=300)
+  real ccf(-MMAX:MMAX,-JMAX:JMAX)        !2D CCF: DT, dFreq offsets
+  complex clo(NMAX)                      !Complex Local Oscillator
+  complex crcvd(NMAX)                    !Signal as received
+  complex c(0:NFFT-1)
+  integer ipk(2)
+  character*1 line(-30:30),mark(0:5)
+  data mark/' ','.','-','+','X','$'/
+
+  ccf=0.
+  df=12000.0/NFFT                         !0.366211
+  i1=ND1*nsps
+  do m=-MMAX,MMAX
+     lag=100*m
+     c(0:nsync-1)=crcvd(i1+1+lag:i1+nsync+lag)*clo(1:nsync)
+     c(nsync:)=0.
+     fac=1.e-3
+     c=fac*c
+     call four2a(c,NFFT,1,-1,1)
+     do j=-JMAX,JMAX
+        k=j
+        if(k.lt.0) k=k+NFFT
+        ccf(m,j)=real(c(k))**2 + aimag(c(k))**2
+     enddo
+  enddo
+
+  ccf=ccf/maxval(ccf)
+  ipk=maxloc(ccf)
+  print*,i0,ipk(1)
+  ipk(1)=ipk(1)-MMAX-1
+  ipk(2)=ipk(2)-JMAX-1
+  ma=max(-MMAX,ipk(1)-10)
+  mb=min(MMAX,ipk(1)+10)
+  ja=max(-JMAX,ipk(2)-30)
+  jb=min(JMAX,ipk(2)+30)
+  do m=ma,mb
+     do j=ja,jb
+        k=5.999*ccf(m,j)
+        line(j-ipk(2))=mark(k)
+     enddo
+     write(*,1300) m/120.0,line
+1300 format(f6.3,2x,61a1)
+  enddo
+  t=ipk(1)/120.0
+  dfreq=ipk(2)*df
+  f=1500.0+dfreq
+
+  return
+end subroutine sync_sf