After checking with Stephan Ukas-Bradley, the US Arri product manager and then talking to Dave Lezynski, a SF DIT who had called Ambient, I found out that the Alexa Timecode system is licensed from Ambient and works like the one in Lockit syncboxes and the Ambient slates.  It can be tuned by the Ambient Master Controller to improve the accuracy to beter than 1 ppm and can be jamed just like the slates or Lockits.  This is the first camera to have an internal clock designed to be jammed and not r