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Entry  Mon Jul 16 19:39:35 2018, Woon-Seng Choong, Effect of interpolation on timing 
    Reply  Fri Jul 20 00:44:13 2018, Woon-Seng Choong, Effect of interpolation on timing 
Message ID: 709     Entry time: Fri Jul 20 00:44:13 2018     In reply to: 708
Author: Woon-Seng Choong 
Subject: Effect of interpolation on timing 

Just a follow-up update.

It turns out that I was using a cubic spline interpolation with smoothing. If I required the cubic spline to go through the sampled points, then I obtained similar time resolution as the simple linear interpolation.


Woon-Seng Choong wrote:

Using a test pulse split into two channels of the DRS4 Evaluation Board v5, I looked at the time resolution using a leading edge threshold. The voltage and timing calibration was performed. One method (1) is to linearly interpolate between two points of the raw waveform that is above and below the threshold (this is exactly the algorithm given in read_binary.c in the drs4 source distribution); and another (2) is to use a cubic spline interpolation of the raw waveform. The results I obtained are:

Method 1: dt = 1.298 ns +/- 7.22 ps

Method 2: dt = 1.293 ns +/- 15.48 ps

I am really puzzled why the time resolution of the spline interpolation is about a factor 2 worse than the simple linear interpolation. Has anyone studied the time resolution using similar or other interpolation methods?




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