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Re: Cable length [was: Contact Information for Electronics]



Hi Gerard,

    I was looking for a table with cable lengths, just like the one Tim 
just distributed. As you know, the 100% design must be in place by this 
Spring and we should have at least a good number for the cable runs. 
This impacts the cost considerably.

    I was also suggesting testing the system under the worst conditions 
(dispersion, crosstalk, etc.). This is especially important before Mitch 
finalizes the ASIC design.

Regards,
Fernando



Gerard Visser wrote:
> Hi Fernando,
>     I'm not sure if you're asking about this - but I don't believe 
> there is any hard constraint from the electronics design that we are 
> approaching yet with 21 m cable lengths. I have a (hastily designed) 
> equalization circuit working with a 21 m cable and it has about 11.7 
> bits of dynamic range and ~7 ns risetime, it should be enough. I don't 
> think we could have 100 m cable, but I think anything less than 25 m 
> is certainly reasonable.
>     To design and test, though, I believe we want to get to more 
> specific planning of the lengths now (or as soon as practical). That 
> was my main point.
>
>     Gerard
>
> Fernando J. Barbosa wrote:
>> Hi Gerard,
>>
>>     Yes, we really need to have a table like the one you suggest. It is
>> especially important to know the maximum lengths given the constraints
>> on shaping, gain and dynamic range for both the fADC-125 and the ASIC.
>>
>> Regards,
>> Fernando
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