That's not a bug, but a feature of the DRS4 chip. The time bins have different values by the properties of the chip. They are generated by a chain of inverters, which all have different propagation times. This delay is measured by the time calibration and then applied. If you want equidistant bins, 
you have to interpolate your data points (linearly or by splines) and resample the signal. You can find more details in the DRS4 data sheet.

Best,
Stefan


> Hi,
> 
> We are using the DRS4 Evaluation Board as a digitizer in our laboratory.
> We found a strange behavior in the saved files, more specifically the time difference between two consecutive points is not constant, also after the Timing Calibration.
> As an example, I paste a piece of a xml file saved using the drsosc program, acquiring CH1 (open):
> 	
> 	---------------------------
> 	---[ START XML EXAMPLE ]---
> 	---------------------------
> 	
> 	<?xml version="1.0" encoding="ISO-8859-1"?>
> 	<!-- created by MXML on Thu Nov  8 11:13:27 2018 -->
> 	<DRSOSC>
> 	<Event>
> 	<Serial>1</Serial>
> 	<Time>2018/11/08 11:13:27.163</Time>
> 	<HUnit>ns</HUnit>
> 	<VUnit>mV</VUnit>
> 	<Board_2796>
> 	<Trigger_Cell>216</Trigger_Cell>
> 	<Scaler0>0</Scaler0>
> 	<CHN1>
> 	<Data>0.000,-1.0</Data>
> 	<Data>1.083,-1.0</Data>
> 	<Data>2.143,-1.0</Data>
> 	<Data>2.926,-1.0</Data>
> 	<Data>4.249,-0.1</Data>
> 	<Data>4.929,-0.6</Data>
> 	<Data>6.075,-0.4</Data>
> 	<Data>7.042,0.0</Data>
> 	<Data>8.299,0.2</Data>
> 	
> 	[...]
> 	
> 	-------------------------
> 	---[ END XML EXAMPLE ]---
> 	-------------------------
> 
> We found the same behavior saving events in the binary format, and then reading them with the read_binary.cpp
> 
> Is there a way to fix our issue?
> 
> Thanks a lot
> 
> Davide and Alessio