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

[Lubomir Pentchev]

Hi Gerard,

Yes, at that time I swapped the cables at the fADC and the timing followed 
the cable, so the fADC is excluded. Then I swapped the cards on the 
chamber and nothing changed, so the chamber is excluded too. Hence, the 
preamps or the cables are the source of the discrepancy. I should have 
swapped also the cables at the preamp side, but I didn't. Now maybe it 
would be easier just to measure the length of the cables to make sure they 
are the same.

Lubomir


On Tue, 17 May 2011, Gerard Visser wrote:

> 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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