Difference between revisions of "FADC Data Format July 22, 2014"
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* [[CDC_algo|CMU timing algorithm - details updated]] | * [[CDC_algo|CMU timing algorithm - details updated]] | ||
* [[CDC_readout_requirements|CDC readout needs]] [[CDC_garfield_calcs|Garfield calcs]] | * [[CDC_readout_requirements|CDC readout needs]] [[CDC_garfield_calcs|Garfield calcs]] | ||
− | * [ | + | * [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=2274 fADC125 Data Format Specification Document] |
* [[File:NSJ_draft_fADC125_spec_4_1.pdf]] | * [[File:NSJ_draft_fADC125_spec_4_1.pdf]] | ||
Latest revision as of 17:02, 24 February 2017
Location and Time
Room: CC F326-327
Time: 2:00pm-3:00pm
Remote Connection
(if problems, call phone in conference room: 757-269-6460)
- To join via Polycom room system go to the IP Address: 199.48.152.152 (bjn.vc) and enter the meeting ID: 462136260.
- To join via a Web Browser, go to the page [1] https://bluejeans.com/462136260.
- To join via phone, use one of the following numbers and the Conference ID: 462136260
- US or Canada: +1 408 740 7256 or
- US or Canada: +1 888 240 2560
- More information on connecting to bluejeans is available.
Agenda
- Previous meeting (June 17, 2014)
- fADC125 operation and data format requirements (June 17, 2014)
- Pedestal
- Status of FADC125 Firmware
Useful Links
- FDC_pulse_data_format
- CMU timing algorithm - details updated
- CDC readout needs Garfield calcs
- fADC125 Data Format Specification Document
- File:NSJ draft fADC125 spec 4 1.pdf
Minutes
Attendees: Naomi (CMU), Cody, Beni, David, Lubomir (JLab)
- Pedestal
- Beni reported that the CDC pedestal noise is horrible, 60Hz noise with amplitude 100 to 300 adc-units, and bursts of 50MHz noise with 200kHz burst frequency.
- As Beni showed previously, the optimum number of samples to use to calculate mean pedestal is 20, in the firmware we have to use a power of 2 number of samples so that the mean can be calculated by right-shifting, there was a huge improvement from mean over 8 samples to a mean over 16 samples, but little further improvement when using a mean over 20 samples, so we will use a mean over 16 samples.
- The mean pedestal will have to be calculated at two points, first just before t0 (time of earliest possible pulse) in order to determine the hit threshold (pedestal + constant) and again after finding the hit pulse, just before the start of the pulse.
- The second mean pedestal is intended for pedestal subtraction and will be written out in the data stream.
- The pedestal subtraction will not be done on board the fadc (in case the mean pedestal exceeds the current data value results in a negative number which becomes represented as something huge instead).
- Status of FADC125 Firmware - Cody has been working on other Hall D tasks for the last week and will be returning to fa125 firmware development soon.