[Halld-cal] [Halld-level1] L1 trigger meeting reminder

[Mark Ito]

Alex, et al.,

One thing I have not seen in the email discussions is the idea of a mode 
where both mode 7 and 8 data come out in the same event. That would 
allow verification of the algorithm (and of any emulation, though 
perhaps not necessary with this mode available), on a pulse-by-pulse 
basis. I would think in such a mode would actually eliminate the need 
for pure mode 8. Reading out both should not increase the data volume 
over mode 8 by a large percentage and if we are reading out raw 
waveforms at all we would not be in a mode where we are trying to push 
the event read-out rate so doing the processing for both modes should 
not bother us. I have mentioned this to Hai before in a hallway 
conversation some weeks ago.

Also, in a previous experiment I was on, we always considered samples 
both before the rising edge of the pulse and after the trailing edge (i. 
e., before high-going threshold crossing and after low-going threshold 
crossing). That ensured capture of the entire pulse, independent of 
pulse amplitude. Also it gave more complete information about 
close-in-time pulses in a single channel that appear as merged pulses; 
not complete, but more complete. It is analogous to having the entire 
pulse visible on an oscilloscope screen. Admittedly, the trailing edge 
is less well defined since the slope of V vs. t (a negative slope if we 
say all pulses are positive going) is much smaller in amplitude, but 
since V itself is small, the effect is not so bad.

At a more advanced level one could think of having more complicated 
processing of pulses where a double pulse is detected according to some 
algorithm. In that case, it might be simpler to pass along the raw 
waveform for such pulses and only such pulses, i. e., go ahead and read 
them out. Such pulses should be a small fraction for the majority of 
channels and thus not create a huge data volume load.

   -- Mark

On 08/09/2015 11:24 PM, Alexander Somov wrote:
>
> Hi,
>
> We are going to discuss with Hai Dong the feasibility to
> implement some features in the new fadc250 firmware during
> the meeting tomorrow (Aug 10th).  The meeting will be in
> our usual place, A110 at 9:30.
>
> Cheers,
>        Alex
>
> P.S. I've updated GlueX-doc-2776, which containes some proposed
> changes.
> _______________________________________________
> Halld-level1 mailing list
> Halld-level1 at jlab.org
> https://mailman.jlab.org/mailman/listinfo/halld-level1