From 883c914d29693bca8c269339df2c6823187fb700 Mon Sep 17 00:00:00 2001
From: Steve Franke <s.j.franke@icloud.com>
Date: Fri, 24 May 2019 20:09:00 -0500
Subject: [PATCH] Make DT=0 mean that the first full symbol starts at t=0.5s.
 Formerly DT=0 corresponded to the beginning of the ramp-up symbol. Fix a bug
 that caused signals with large DT to wrap around instead of truncating them.

---
 lib/ft4/ft4sim.f90 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/ft4/ft4sim.f90 b/lib/ft4/ft4sim.f90
index e35e5ad8a..959cf423c 100644
--- a/lib/ft4/ft4sim.f90
+++ b/lib/ft4/ft4sim.f90
@@ -110,8 +110,10 @@ program ft4sim
   c0((NN+1)*NSPS:(NN+2)*NSPS-1)=c0((NN+1)*NSPS:(NN+2)*NSPS-1)*(1.0+cos(twopi*(/(i,i=0,NSPS-1)/)/(2.0*NSPS) ))/2.0
   c0((NN+2)*NSPS:)=0.
 
-  k=nint((xdt+0.5)/dt)
+  k=nint((xdt+0.5)/dt)-NSPS
   c0=cshift(c0,-k)
+  if(k.gt.0) c0(0:k-1)=0.0
+  if(k.lt.0) c0(NZZ+k:NZZ-1)=0.0
 
   do ifile=1,nfiles
      c=c0