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Entry  Sat Apr 2 11:21:10 2016, Felix Bachmair, Question about timimng calibration 
    Reply  Sat Apr 2 11:41:07 2016, Stefan Ritt, Question about timimng calibration 
Message ID: 496     Entry time: Sat Apr 2 11:41:07 2016     In reply to: 495
Author: Stefan Ritt 
Subject: Question about timimng calibration 

The evaluation board normally has 1024 bins per channel. We offer an option with 2048 bins using channel cascading, to capture longer waveform windows. The binary data format is however defined as having 1024 bins. Therefore, for the 2048 bin boards, the software averages over two adjacent cells and saves effectively 1024 bins. The noise of each bin improves this way by sqrt(2). The time however is not very well defined, since you average the voltage of two bins. Therefore, I simple also average over the time of the two bins. Maybe this is not the best way, so feel free to change this.


Felix Bachmair wrote:


I am trying to understand some details about the timing calibration.

We wrote our own code but we more or less use the ideas of the Oscilloscope class.

In the binary file writing of in the function Osci.cpp::SaveWaveforms() (line 924ff)

the following code is executed:

if (m_waveDepth == 2048) {
    t = (tcal[j]+tcal[j+1])/2;
} else
    t = tcal[j];


I do not understand the averaging of the to adjacent calibration constants. Could you explain this? Do one have two measurements?






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