We see quite some spikes in our DRS4 sampled data in FACT.  We see different types of spikes:

• single cell spikes, usually showing a large amplitude of 200mV
• double cell spikes, usually only in the order of 20mV.
• Even triple and quadro cell spikes are rarely seen.

The double cell spikes often occur as symmetrical double cell spikes mirrored at cell 512. quadro cell spikes seem to be nothing else, than connected symmetrical double cell spikes. For the triple cell spikes we have no idea.
Currently we use simple filters to get rid of these spikes, this workes rather well for the large single cell spikes, but with the occurance of tripples and quadros we started to worry about higher multiples and revived our DRS4 spike investigations.

Now I was told, that you Stefan know already where these spikes come from and even a paper exisits. Unfortunately so far I was unable to find it.
I wonder if it is possible to predict the occurance of these spikes, so one does not have to search for them anymore and can get rid of the filters.

Best regards

Dominik

Unfortunately the simultaneous writing/reading does not work as described in the data sheet. Just recently we found out that due to a bug in the chip a part of the waveform is missing if you read and write at the same time. The only clean solution is to use two DRS4 chips in parallel. You read one chip while the other samples, then you switch over between them. In that case all the ROI scheme and channel cascading works normally. The dead time will be addressed by the DRS5 chip, which will be dead time free, but will not be available until in maybe 2-3 years.

/Stefan 

Hello!

We're developing electronics based on the DRS4 to read out a breast PET scanner and our event rate will be quite high so we're concerned about dead-time.  with that in mind, I have a question regarding the mode of simultaneous writing and reading that is described in the DRS4 data sheet.  I think the description there is quite clear but I'd like to ask for a few clarifications.

1) Are the channels required to be read out via the channel multiplexer when doing the simultaneous write/read or is it ok to read out all channels in parallel (even the ones still sampling) and just throw away the ones you don't want?

2) If one wanted to use region of interest mode along with the simultaneous write/read, how would that work?  Here is what I would think - please tell me if I'm missing some important detail:

-upon trigger, deassert dwrite.

-strobe RSRLOAD

-increment write config register

-reassert dwrite

-start the readout (reading out stop shift register value on SROUT as data comes out)

3) now to add even more complexity - I would actually like to use simultaneous write/read along with region of interest mode and also with pairs of cascaded channels as we need >500ns latency and 2Gsps is too slow for our signals.  the combination of cascading and simultaneous write/read is addressed in the data sheet but I still have one question.  In normal circumstances when cascading channels, one would read out the value in the write shift register to know which channel was active when the domino wave stopped.  I assume that this is not possible when dwrite is enabled as the write shift register is then advanced by the domino wave, so I see three possibilities:

-accept more dead-time and read out the write-shift-register each time (adds ~240ns to deadtime)

-just read out both channels every time and figure out later where is the data you want

-attempt to keep track of the expected state of write-shift-register in firmware.

is there a better option that I have not thought of?

many thanks!

Benjamin LeGeyt

Yes, but this is documented in the evaluation board manual. You have to modify the script slightly. I will update it myself in about 2-3 weeks.

Cheers,

Stefan

Thank you for your fast and very helpful replay.

I made it work with drsosc version 4 but with version 5 i am getting weird results. Is it possible that they changed binary formatting?

You look here: elog:262

/Stefan

Hi,

Does anybody have program for conversion from binary or xml to cern ROOT *.root file?
 

Thank you for any help you can provide,
Luka Pavelic


 

 Hi Stefan,

you were right, I forgot to install the libusb driver.

Thanks for your support

 Hi,

   I want to describe this phenomenon again. The diagram below is DRS4 output. There is no input signal. Green is the output8+, blue is the output8-. Output8+ of the first channel is below  the baseline. The output is saturation when input ADC. It is not right, and what is it  in front of the first channel? It seemed there are two channels.  Others channel  is suitable. I check the circuit , Hardware is no problem, so I want to konw where the FPGA code  is wrong. What reason is caused? Can anyone help me to solve the problem? Thanks!

> 
> Dear Stefan
> 
> I am trying to use the DRS4 eval board on a Windows7 machine. Unfortunately I get an error message saying "No DRS 
> board found". But I can see the DRS board in the device manager with the proper driver loaded. Is there any known 
> problem with win7?
> 
> I am using windows7 professional (SP1) with the drs software 5.0.1.
> 
> Cheers,
> Roman
> 
> PS: Everything is working on my mac. But not under windows7.

Hi Roman,

please read section 2.3. (page 13)  from the Evaluation Board manual: http://www.psi.ch/drs/DocumentationEN/manual_rev50.pdf

You have to update the USB driver in your Computer Management.

Cheers,
Stefan 

You are funny. Just by looking at a scope picture I should know what is wrong at your FPGA code. Unfortunately I'm not a magician. I looks to me like you have 11 channels in your diagram, although the chip has only 9. What I would recommend is to put some input to each channel one at a time, like a 10 MHz sine wave. You should then see that sine wave for the single channel at the output and can correlate input vs. output. Maybe your address bits are wrong or the chip has a soldering problem.

/Stefan 

Have a look at the web site http://www.psi.ch/drs/software-download . Under the MS Windows section it says that you have to install the libusb-1.0 package first before you can compile the example program. This is also obvious from the missing _usb_* functions in the error listing above.

/Stefan

 Hi,

 The diagram below is DRS4 output. Green is the output8+, blue is the output8-. Output8+ of the first channel is below  the baseline. It is not  right.

Others channel  is suitable. I check the circuit , Hardware is no problem, so I want to konw where the FPGA code  is wrong. what reason is caused? Thanks!

Hi,

when I try to compile drs_exam project my computer give me this output:

1>------ Rebuild All started: Project: drs_exam, Configuration: Debug Win32 ------
1>  averager.cpp
1>c:\users\daq\desktop\

Dear Stefan

I am trying to use the DRS4 eval board on a Windows7 machine. Unfortunately I get an error message saying "No DRS 
board found". But I can see the DRS board in the device manager with the proper driver loaded. Is there any known 
problem with win7?

I am using windows7 professional (SP1) with the drs software 5.0.1.

Cheers,
Roman

PS: Everything is working on my mac. But not under windows7.

Thank you very much for the corrections. I know it in principle, but neither my Mac OSX nor the Windows compiler complains, so I usually don't see this errors. It's fixed now.

/Stefan 

Hi,

the latest software drs-5.0.0.tar.gz fails to compile on my freshly installed SuSE 13.1 whereas the previous 4.0.1 is compiling out-of-the-box.

My system has the wxWidgets 2.8.12 which is probably together with gcc 4.8.1 the reason of the problem. I applied a number of corrections, mainly some sort of proper (?) typecasts, a patch file is attached.

Maybe you could consider to take them into account for the next patch release?

Thanks and best regards

Hermann-Josef

The new software for the V5 evaluation board has been released today with following new features:

• Hardware scalers for all four channels and the trigger working up to 200 MHz. With the trigger scaler one can measure for example coincidence rates between two channels.
• New vertical and horizontal "slice" measurements. This allows to measure the amplitude of a signal at a certain time relative to the trigger point or the time when a signal crosses a certain level.
• Gated charge measurement allowing to measure the charge of a signal between two time markers, like an old-fashioned charge integrating ADC.

The software is available at the the usual location http://www.psi.ch/drs/software-download for Linux, Windows and Mac OSX. I'm working right now to get it also into the Apple App Store.

/Stefan

Time calibration has been changed completely in meantime. With the new V5 boards, we have a new oscillator on the board where on can calibrate each channel individually. This is necessary to obtain a good timing down to a few ps. With the current code the above problem has vanished. We also learned that the time calibration is very stable (less than a ps) over several months, so no need to repeat the calibration over and over again.

/Stefan 

Did you have any progress with that? Unfortunately I don't have a Windows 8 machine here at our institute, so I cannot reproduce your problem. At least I put the 1.2.6 libusb driver into the V5 software package.