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.

Attendees: Naomi (CMU), Cody, Beni, David, Lubomir (JLab)

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.