[Halld-tracking-hw] ADC125 as a TDC...

[Beni Zihlmann]

Hi Gerard,
attached is a 2d plot showing for strip 11 the Maximum Amplitude after 
threshold
vs the time difference with the wire time (any wire). The threshold is 
350 above
pedestal. (The Max amplitude is pedestal subtracted.) So you see there 
is a huge
time walk.

cheers,
Beni
> Hi Lubomir,
> 	I think you checked it before when this was first discovered, but let me ask
> again because I don't recall it really: If you swap cables at the ADC board, the
> timing basically follows the cable? So it is not that the ADC board has a large
> time offset between channels? That would be highly unexpected but I guess not
> impossible, so it would be good to make this check.
> 	Similarly swapping cables at the preamp board would rule out the cable as the
> source of the delay discrepancy...?
> 	If the above is all true, have you tried more than just the two preamp boards?
> Maybe one of them is simply broken?
> 	Sincerely,
>
> 		Gerard
>
> On 5/17/2011 12:43 PM, Lubomir Pentchev wrote:
>> Beni,
>>
>> You can also look at the time difference between the top and bottom
>> strips, compare it with what you have, "t_wire - t_strip", and then you
>> can extract the wire resolution alone.
>>
>> I also don't understand the reason for the big time shift between the two
>> preamp cards, and for the time variations within the cards.
>>
>> Lubomir
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