History: Helicity

GeN experiment utilized a delayed G0 helicity mode. Timing diagram for main signals
used to obtain helicity information presented on following figure.

::{img src=http://hallaweb.jlab.org/experiment/E02-013/wiki/show_image.php?id=77}::

Main signals used for obtaining helicity information in G0 mode are:
1. __MPS__ - 30 HZ master pulse, used as gate for helicity signal.
2. __QRT__ - Showing the beginning of new helicity quad.
3. __Helicity__ - signal showing helicity sign.
In addition we used another signal which is not directly related to helicity information that is
4. __105 kHz clock__ - signal used to reconstruct MPS or QRT signals missed due to some reasons(eg DAQ deadtime) and recover our position in the helicity sequence as well as the position in quad.