F1 TDC Meeting (fwd)

[Elton Smith <elton@jlab.org>]

---------- Forwarded message ----------
Date: Fri, 12 Jan 2001 16:14:06 -0500
From: Fernando J. Barbosa <barbosa@jlab.org>
To: Elton Smith <elton@jlab.org>
Cc: Ed Jastrzembski <jastrzem@jlab.org>
Subject: F1 TDC Meeting

Hi, Elton. I hope you doing well. I and Ed have had a number of meetings on the F1 TDC and we will be glad to present our developments at the next Hall D meeting (Wed., Jan 17th).
    Here are some topics that will help you setup the agenda:
    1.    The F1 TDC chip can be used for high resolution (60pS, 4 channels per chip), normal resolution (120pS, 8 channels per chip) or low resolution (4.5nS, 32 channels per chip). We would like to implement a TDC that offers most of the capabilities of the chip so that it can be used for a variety of detector technologies. Is there use of the TDC in low resolution mode? What is the number or ratio of high and normal resolution requirements? Mechanical, cabling, connectors are considerations.

    2.    Should we standardize the input signals as differential ECL for compatibility with present systems?

    3.    The F1 tdc has facilities for setting up DACs for use as threshold adjustments of discriminators, etc. Should we use these feature and include DACs on the board (maybe over the 17th pair) to set thresholds? Or not use this feature and use a separate system for such, instead?

    4.    In addition to differential inputs, each chip has Start, Trigger and Syncres inputs that will be made available at the front panel. Should we use one set of these inputs for all chips on a board?

    5.    Single channel Rates? (VERY IMPORTANT)

    6.    Memory Depth and architecture? This depends on item 5. (VERY IMPORTANT)

    7.    Crate readout architecture (Push/suck data, Master/Slave arbitration)? (VERY IMPORTANT)

    We estimate spending a considerable time on items 5-7 as most of the back end of the board depends on these. Most likely, we will need a series of timely meetings to get a consensus on these issues.
    Best regards,

Fernando J. Barbosa
Jefferson Lab,
Physics Div., MS 12H
12000 Jefferson Ave.
Newport News,  VA 23606

Phone: 757-269-7433
Fax:  757-269-5800
Email: barbosa@jlab.org