An update. I have been successful in making modifications to drs_exam.cpp so that I can get 2048 samples per channel.. The main changes were to the size of the time_array and wave_array and adding a call to Set ChannelConfig(0,8,4). It was also necessary to change the parameters to GetWave so that the Trigger Cell and WSR values were passed to get the channel combinations correct (2048 channel.ppt).

I've moved on to try to increase the speed of acquisition (I get only about 500 events/sec) and trying to understand the corrections.Working through the source code slowly...

Regards,

Larry Byars

I am trying to compile drs-exam, but am getting an error message I do not understand:

1>musbstd.obj : error LNK2019: unresolved external symbol _usb_open referenced in function _musb_open
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_close referenced in function _musb_close
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_get_descriptor referenced in function _musb_get_device
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_bulk_write referenced in function _musb_write
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_bulk_read referenced in function _musb_read
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_set_configuration referenced in function _musb_open
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_claim_interface referenced in function _musb_open
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_release_interface referenced in function _musb_close
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_set_altinterface referenced in function _musb_set_altinterface
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_reset referenced in function _musb_reset
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_init referenced in function _musb_open
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_set_debug referenced in function _musb_open
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_find_busses referenced in function _musb_open
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_find_devices referenced in function _musb_open
1>musbstd.obj : error LNK2019: unresolved external symbol _usb_get_busses referenced in function _musb_open

I have tried redownloading a different version of libusb-1.0, but the problem was not solved.  What might I be doing wrong?

surrey i forgot to update..

after carefully examining our VHDL we found out that there are brief times that we put A0-A3 in 1111

after making shore that a0-a3 never get 1111 value thae drs4 woks as expected.

The dtap toggols ok.

We can sample and read all the data channels.

So, putting A0-A3 value of 1111 even for very short period  " confuse " the DRS and then it start to behave in a strange manner.

mony

I am attempting to use the DRS4 to measure the timing resolution of a pair of SensL silicon photomultipliers (SiPM). In order to do this I need to trigger the DRS4 only when there is a coincidence between the two input signals, and hopefully make histograms of the relative detection times of each detector.

There are two completely separate issues. (1) I think this may just be a labelling error. In the first image (OR_mode_selected) one can clearly see two pulses which are very similar. In this mode, both signals are present, and are always present. I think this should be the "AND", not "OR" of the two signals. Contrast this with the second image where I have selected "AND_mode". Clearly only one signal is present, and either signal trigges an event, so this should be "OR", not "AND"

The second issue is, for me, much more serious. I want to sample the leading edge of this event in order to determine its "time". The little "T" at the top of each image is, I believe the "trigger point" in the first two images. However, this is well after the part of the signal I am interested in. The first two images were at 2 GigaSamples/sec. The third is at 5 GigaSamples/sec. Clearly the event I am interested in processing is over by then. At the lower sampling rate, I can see well before the "T", but at the higher one I can only see after the "T". I had built an external "coincidence circuit" and the "external trigger mode" hoping to to circumvent this issue by using very long cables to delay the signals inut to the DRS4, But even then I have not been successful in getting the to work.

I am using version 5.0.3 on a PC as the version released after that did not work.

I hope some can help!

Chris Thompson

I would really love to be able to save histogram data, though I have not been able to do this. I could take a screenshot and extract the data from an image, but would prefer to avoid this if there is a simpler way... possibly I have overlooked something obvious? Thanks very much for any advice or tips.

Hello! My name is Dmitry. I am from SiPM Lab is NRNU MEPhI (Russia, Moscow). We bought DRS4 evaluation board V5 with firmware 21305. We use 5.0.4 build 21911 2015-11-23 software version (and before that we used 5.0.3 build 21508, 2014-10-15) with Windows 7 32bit.

We observe some strange behaviour. When we save waveforms (in xml or binary data) we see that some of them have the baseline shifted of about -5 mV.

The first picture (pic1) is 1000 waveforms which were glued in one. It is clearly see that baseline quite often has the shift.

The same effect can be seen without saving (writting): rarely when we use normal or auto trigger mode (pic3), and always in single trigger mode (pic2).

The images are attached.

Do you have any idea how it can be fixed?

Thanks, Dmitry.

Dear Stefan,

I daisy-chained two boards (master sn#: 2514 - slave sn#: 2513) each with 2048 samples. However, when I use drsosc and put check mark in "configure multi-board daisy-chain" I see only 1024 samples. Namely, the first 1024 samples, the last part is missing. When I remove this check mark, I see all 2048 samples. Is there a simple software fix for this or is it a more involved firmware limitation? 

Other parameters: software version: 5.0.4, firmware version 21305, configured for 0.7 GSPS, display at 500 ns/div

Thank you,

Dmitry Hits.

Hello Stefan,

I just stumbled again over a phrase in the DRS4 datasheet I never really understood, but didn't find the time to ask.

On page 8 it says: "An internal circuit ensures that the write signal is always 16 cells wide."

So when I look at a single channel, do I understand correctly, that at any given time during sampling, always 16 cells are open, i.e. 16 cells are connected to the analog inputs? So when the domino frequency is e.g. 5GHz then each cell sees the analog input not for 200ps but for 3.2ns correct?

I would like to be able to trigger in this fashon:  channel 0 > 0.1 and. channel 1< -0.1,  because I have a positive and a negative signal.  Can DRS4 (5) Eval board do this kind of trigger?

Thanks!

Abaz

Ok, thanks!  do you know an easy in-line inverter like mini-circuit or digikey?    Can also redesign the detector I gues to produce positive signals, just it might be easier if there was a simple inverter if you are aware of? thanks Abaz

Hi,

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;
    j++;
} 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?

Cheers

Felix

Dear Stefan Ritt,

I am using a DRS4 v5 to do timing measurements of Positron lifetime. I use the DRS Oscilloscope with triggering on 2 channels when I have a coincidence. Attached is a picture with all the setting that I use. When I use the DRS4 for a long measurements of 5 million events for a couple of hours, the DRS Oscilloscope stops showing any signal .After the first restart of the program I get a strange signal which is at the bottom of the scope range of voltage picture below(in the picture I changed the vertical positions of the channels for better viewing). Only after a couple of DRS Oscilloscope restarts and USB reconnections do I get the results again.

I currently am using another DRS4 v5 and the same situation occurs again although with lower frequency.

What can I do to solve this problem?

thank you very much,

Daniel

Dear Stefan Ritt,

Yes I use Windows 7, If the DRS Oscilloscope program stays on for a couple of hours without saving the data, the problem will occur. It seems it happens more often when there is data writing and when the rate of events is slow, about 100 events per second, at high rates it almost doesn't happen. Can it be temperature related?

Daniel

Then it seems that there is some USB communication problem. I heard this also from other people, that the USB data transfer under Windows has sometimes problems. I develop and run the board under Mac OSX, and there the same software runs for days without problem. So I guess it's related to the underlying libusb lib which is used by the DRS oscilloscope, on which I have no influence. So the only advice I can give is to take shorter series of data. Anyhow the board is not considered a full DAQ system, just an "evaluation board" which means one can try the DRS4 chip and play with it. For serious business one should build own electronics with the chip. Anyhow we are currently developping an Ethernet board which allows much faster acquisition rates, so USB will be obsolete some day. Nevertheless I will try to reproduce your problem and see if I can do anything. At what trigger rate does it show up most prominently?

Stefan

Hi Kyle,

If I remember right the negative sampling width happens only for 498 and at high sampling speeds. It is described in a paper from Stefan:

http://arxiv.org/pdf/1405.4975.pdf

or

“Novel Calibration Method for Switched Capacitor Arrays Enables Time Measurements With Sub-Picosecond Resolution”( IEEE Transactions on Nuclear Science 61 (2014),Nr. 6, 3607–3617)

    Hi,

 I can't contact with Anita Van Loon about DSR4 chip's price and delivery.

Did you still sell it? Can you provide me this information?

Dear all,

I'm using 3 DRS boards simultaneously and their serial numbers are 2169, 2170, 2172 respectively.

Recently however,  I obtain serial number "0" by DRSBoard::GetBoardSerialNumber() for #2172 board.

Data taking can be done without any problems, but I'd like to know what is happening.

Any advice？

Thank you.

Toshihiro Nonaka

I am studing some pulses that are about 200-300 ns wide and a rise time of few ns,    which settings would be best for coincidence time measurements?

In some preliminary work I found for 700 MegaS the time measurement is better without time calibration (in -0.05 to 1V) rather than with time calibration in -0.5 to 0.5,  my pulses are about 60 mV.   Is it expected that always with time calibration time accuracy would be better or depends?   

Also I use this code snippet to find time for channel 1 and the same idea for chan. 2.

// find peak in channel 1 above threshold
      for (i=0 ; i<1022 ; i++)
         if (waveform[0][i] < threshold1 && waveform[0][i+1] >= threshold1) {
            tt1 = (threshold1-waveform[0][i])/(waveform[0][i+1]-waveform[0][i])*(time[0][i+1]-time[0][i])+time[0][i];
            break;
         }

Thanks!

Abaz