[d2n-analysis-talk] 60Hz filters on ADCs

[Brad Sawatzky]

Hi Matt,

I just realized my brain stalled when we were talking about the 60Hz
filter today (part of the pedestal noise discussion).  We certainly did
have high-pass filters just before the signals entered the ADCs.  You
even pointed me at a couple of HALOG entries indicating a problem with
one of those little filter packs a week ago:

>   The only thing I could find on pmts 6 (a 60Hz filter change on Feb. 13)
> and 12 (pmt base change on Feb.16)  were these:
>     http://www.jlab.org/~adaq/halog/html/0902_archive/090213211141.html
>     http://www.jlab.org/~adaq/halog/html/0902_archive/090215224231.html

In the first link, the filter (which is just a simple RC circuit) had a
bad/broken solder joint so no signal at all was getting through.  The
ADC signal for those runs was probably a very narrow peak (ie. the
intrinsic ADC pedestal).

I just wanted to clarify this -- I'm pretty sure I said something
stupid/confusing during the meeting...  Sorry about that.

-- Brad

-- 
Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
  Ph: 757-269-5947 -<>- Pager: 757-584-5947 -<>- Fax: 757-269-7848
The most exciting phrase to hear in science, the one that heralds new
  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov