From - Sun Jun 24 15:36:11 2001 Received: from trmail.triumf.ca (trmail.Triumf.CA [142.90.100.150]) by sitka.triumf.ca (980427.SGI.8.8.8/8.8.5) with ESMTP id OAA24014 for <renee@sitka.triumf.ca>; Wed, 30 May 2001 14:43:12 -0700 (PDT) Received: from triumf.ca (bennettpc.Triumf.CA [142.90.106.6]) by trmail.triumf.ca (8.10.2/8.10.2) with ESMTP id f4ULhCL17355 for <renee@triumf.ca>; Wed, 30 May 2001 14:43:12 -0700 Message-ID: <3B15699F.1413438E@triumf.ca> Date: Wed, 30 May 2001 14:43:59 -0700 From: Peter Bennett <bennett@triumf.ca> Organization: TRIUMF X-Mailer: Mozilla 4.7 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Renee Poutissou <renee@triumf.ca> Subject: Re: Postamp controller docs References: <3B155B25.7E1E55FA@triumf.ca> <3B156013.92C7E636@triumf.ca> <3B1567D4.8A31C9C@triumf.ca> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Renee Poutissou wrote: > > Peter > > Thanks for the reply. I guess this means that there is no > programming of the PACT. It is just a device for which we can > monitor crate voltages and temperature. > > Can you explain then what happens in the PACT? or should I ask > John Shapman? > > Renee > There is a test pulse that you can play with, same as on the postamp. I don't know what the MQT300s do with the signals... Here's a note John sent to me today: =================== Hi Peter, The mod I'm doing now is for increasing the test pulse injected into the inputs so that there is still a usefull size output when the preamp cables are connected. It was pretty hard to predict the R C values we would need beforehand. I have replaced C 81 1n0 with a zero ohm jumper, R 276 from 750 to 392 and C78 from 68 pF to 220 pF. With these values you will get output that is 3/4 F.S. with input cables connected and F.S. with test pulse amplitude set to 1600 without input cables. Since the test pulse doesn't decay to zero before the gate closes ( since we are using gates in the 100 - 200 nsec range )there will be readout variation with changing gate width to be aware of as well as the variation in pedestals with gate width. It's kind of a compromise we will have to live with. Test pulse output with the long delay cables will be slightly different because the reflection will arrive after the gate is closed; a benefit for once! John ================== -- Peter Bennett TRIUMF 4004 Wesbrook Mall, Vancouver, BC, Canada GPS and NMEA info and programs: http://vancouver-webpages.com/peter/index.html