fADC stop pointer

[Yves Van Haarlem <yvhaarle@ernest.phys.cmu.edu>]

Hall D Electronics:

Hi All,

I did a test concerning fADC timing, it is described in:

http://www.jlab.org/Hall-D/software/wiki/index.php/FADC_timing

In short: it turns out that the stop pointer returned by the fADC jumps 
around (~20ns or 4 bins) - I believe this should not be the case. This 
test was performed using the internal clock in the fADC - I will repeat 
this test with the external clock. This behavior is confirmed by Gregg 
Franklin an Diana Parno who use the same fADC with different readout 
software for the Hall-A polarimeter upgrade (they saw a cut-off at the 
end and I saw the rising edge moving -- see description on the website).


Cheers,
 	Yves



                           /--------------------------------
                          /   Yves Van Haarlem
        _--~~--_         /
      /~/_|  |_\~\      /      Carnegie Mellon University
     |____________|    /        Department of Physics
     |[][][][][][]|:= /          Wean Hall room 8404
   __| __         |__ \       	 Pittsburgh, PA 15213
  |  ||. |   ==   |  | \           USA
(|  ||__|   ==   |  |) \
  |  |[] []  ==   |  |   \   	    Tel.:   +1 412 268-6949
  |  |____________|  |    \                  +1 412 641-9252
  /__\            /__\     \	      Fax.: +1 412 681-0648
   ~~              ~~       \-----------------------------------