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Entry  Thu Jun 12 12:40:03 2014, Roman Gredig, DRS eval bord v5 Timing eqn1.png
    Reply  Thu Jun 12 12:46:00 2014, Stefan Ritt, DRS eval bord v5 Timing 
Message ID: 354     Entry time: Thu Jun 12 12:46:00 2014     In reply to: 353
Author: Stefan Ritt 
Subject: DRS eval bord v5 Timing 
> a) Calibration:
> I am using 4 boards daisy chained. To achieve optimal time resolution I did first a voltage calibration and right afterwards a time calibration. For all 
> boards after the master I am not sure how to do it.
> After setting the flag "Configure multi-board daisy-chain" in the config menu, all the slave boards set the flag "use external reference clock".  By 
> hitting the voltage calibration button, the slave boards unset this flag. Is it true, that I have to re-set this before doing the time-calibration right 
> afterwards?

Please do NOT do any calibration in multi-board mode. This will not work. Calibrate the boards separately, then activate the multi-board mode. Please note that the timing between the boards is not better 
than ~50 ps. This is a limitation of the FPGA clock generators. If you need better timing, you have to feed an external clock into one channel of each board (leaving only 3 channels for DAQ). The upcoming 
WaveDREAM board will have 16 channels per board, so building bigger DAQ systems will be much easier (and more precise).

> b) getting the right times in binary format:
> To get the time out of the time width (i.e. the t_ch[i]) you sum up in your documentation from j=0 to j=i (see attachment). In your example code 
> read_binary.cpp (line 113) you sum from j=0 to j=i-1. Since you get the the bin with in the binary file, I guess that the example code is correct one?

Yes, I will correct the documentation.

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