diff --git a/drivers/SpinCore-PulseBlaster/SpinCore-PulseBlaster.cpp b/drivers/SpinCore-PulseBlaster/SpinCore-PulseBlaster.cpp
index 8c43971..eaed955 100644
--- a/drivers/SpinCore-PulseBlaster/SpinCore-PulseBlaster.cpp
+++ b/drivers/SpinCore-PulseBlaster/SpinCore-PulseBlaster.cpp
@@ -178,7 +178,7 @@ void SpinCorePulseBlaster::run_pulse_program_w_sync(state& exp, double sync_freq
     c=prog->create_command();
     c->ttls=sync_mask;
     c->instruction=SpinCorePulseBlaster::WAIT;
-    c->length=shortest_pulse*2.0;
+    c->length=shortest_pulse;
     prog->push_front(c);
 
     if (1) {
@@ -188,11 +188,10 @@ void SpinCorePulseBlaster::run_pulse_program_w_sync(state& exp, double sync_freq
         // reported to SpinCore  (Contact Request 2016-12-19 at 1482143561)
         // markusro: When is this necessary? (TODO)
 	    c=prog->create_command();
-	    //c->ttls=sync_mask;
-	    c->ttls = 0x0;
+	    c->ttls=sync_mask;
 	    c->instruction=SpinCorePulseBlaster::CONTINUE;
 	    //c->length=shortest_pulse+2; //
-	    c->length=12; // markusro: why shortest_pulse+2=11  , tests show 120 ns minimum state time??
+	    c->length=12; // markusro: why shortest_pulse+2=11 (110ns), tests show 120ns minimum state time for some PBs?
 	    prog->push_front(c);
     }
     duration+=2.0*shortest_pulse/clock+1.0/sync_freq;