PCB form factor (fwd)

[Elton Smith <elton@jlab.org>]

---------- Forwarded message ----------
Date: Tue, 27 Feb 2001 13:37:40 -0500
From: Fernando J. Barbosa <barbosa@jlab.org>
To: Paul Smith <ptsmith@indiana.edu>
Cc: Ed Jastrzembski <jastrzem@jlab.org>, Elton Smith <elton@jlab.org>
Subject: PCB form factor

Hi, Paul. How are you? I hope things are moving well on your project(s).
    We are presently finalizing the specifications on the TDCs and it would be nice if the ADCs and TDCs could share the same DAQ system. At present, the TDCs may be used in low resolution mode (64 channels, 100 pS resolution) or high resolution mode (32 channels, 50 pS resolution) and these cover all requirements for Hall D, as well as, future upgrades to the existing Halls. VME64X has been chosen as the interface standard, although some questions still remain. One of these concerns the form factor. A 6U form factor seems to fit our TDC requirements. Have you chosen a form factor for the ADCs? I believe the ADCs will require more board space, maybe a 9Ux400 mm. Is this reasonable? For standardization, we may have to implement the TDCs in this same format so that TDCs and ADCs can be used on the same crate, if needed. Standardization of crates may also lower the cost slightly due to the economy of scale.
    Best regards,

        Fernando