Dear Daniel,

sorry my late reply, I'm pretty busy these days. The behavior you report has not been seen before, but I guess no one tried to take such long runs of data yet. Can you confirm that the problem also occurs without writing data to disk, or is it disk-related? I guess you use it under Windows 7, right?

Stefan

Thanks, great!

No there are no other components. I put a photo of the inverter with its cables SMA and one end, BNC at the other. You can see it is very small. I glued the inverter to a piece of thin plywood, and fixed the cables to it before attempting to solder them to the pads on the ferite bead support

Thanks again,   this is very useful,  just another question did you put any other passive elements in the circuit for inverting the signal or just simply swaped the transformer connections? 

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.

Stefan

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

The coilcraft part number is: JA4220-ALB. Iordered two of them and they were sent as free samples. You might want to buy some slightly bigger ones. I found them so small it was very hard to solder the coax cable to the connectors. Since I got them, I managed to damage one as they are quite fragile! In the confirmation email I got there was some contact info which may be useful for you: "For help, contact Victoria Berner at 847-516-5551  vberner@coilcraft.com "  BTW every time I use this forum I'm told that my password is not valid. Each time I reset it according to the "Lost pasword preceedure. Then I can log on again. Its quite annoying.

Hi Chris,

 I am looking at Sensl SiPMs as well,  can you send the part number from Coilcraft?

Thanks!

Abaz

I needed a fast pulse inverter in order to feed signals from the recent SensL SiPMs into a conventional CFD which only accepted negative signals. I got a very small ferite torridal transformer from Coilcraft and wired up to invert signals then inserted into in 50 ohm coax cable and it works fine. These things cost only a few cents each!

Thanks, that looks just fine.

Here is one (SI 100): https://www.picoquant.com/products/category/accessories/adapters-splitters-cables-various-accessories-for-photon-counting-setups

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

No. You have to use an inverter for one of your signals.

Stefan

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

Yes this is correct. But it is a sample-and-hold circuit. So the sampling cell follows the input for 3.2 ns, then samples and holds the current value at the end of the period.

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

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?

Hi,

I would like to use the DRS4 board with LabView for fast readout.
Do you know anyone who has written a VI for that?

Thanks,
Christian

The multi-board mode has never been tested with 2048 samples, so is very likely not to work. I don't know yet how much work this will be to fix, but I'm on a business trip the next three weeks and probably will only have time to look at it when I return.

Stefan

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.