[RTTY] What 2Tone measures

[aflowers at frontiernet.net]

I asked G3YYD how the stop bit measurement works.  Since people might be tweaking things it would probably be good to know what exactly we are lookingand just as importantly what we aren't.  
 
In summary, the stop bit length is determined by measuring the frame duration from start bit to start bit and subtracting 6 bits (the start bit and 5 data bits).  2Tone displays a running average of 8 characters with high/low thrown out.  So, it really shows you an average character rate assuming the data and start bit average out to 22ms each  (i.e., character spacing minus 132ms).  I doubt that it would show evidence of clock jitter like what EXTFSK can produce, since that will almost certainly average out to look correct over 8 characters.
 
I hope that's helpful.
 
Andy K0SM/2