Distorted analog signal in new GUI

[A-oz]

Hello everyone,

We have an Open Ephys Acquisition board and recently updated to the new GUI.

Since the update took place we are getting a distorted signal from analog outputs. 

We made sure it is not related to the eye tracker itself, by using a function generator and oscilloscope. Everything works as expected but the oscilloscope does not match what we see in the GUI (Please see attached. Signal in ADC 1 start higher than zero, shape are not representing the signal as they should and appear discretized).

We suspect it's a gain issue, the software seems to amplify the signal and discretize it. But can't find any where to define/change the gain for ADC 1.  We didn't had this issue in an older version of the software, so most likely it is not the  Acquisition board itself, which was working fine before. 

Best,
Aviad

[Josh Siegle]

Hi Aviad,

If you click the "ADC" button in the LFP Viewer (next to the "range" ComboBox), does that fix the problem? It's possible it's just a visualization issue.

Does the issue persist if you connect your signal to an alternative analog input channel? And have you tried recording the data to confirm that the offset shows up there as well?

Josh 

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[A-oz]

Hi Josh,

Thank you for your reply. 
We are positive this is not a visualization issue. Notice that the visual we are inserting is smooth, while the output is not. It is most likely the way the signal is being digitized (see below what we think is probably the issue). 

But just to be clear,  we think it is most likely not a gain-software nor it is related to the signal itself as well:
-Eye tracking signal gets distorted as well 
- the MATLAB output is similar to what is being visualized in the GUI, not what we are seeing on the oscilloscope.
- we are using OE I/O board, and made all the related checks (ground, switching channels, switching cables). 

A potential issue is the compatibility between the new GUI (0.6x) and our first generation acquisition board.
Other than the fact that this problem appeared after we upgraded the system to WIN 11, and our GUI to 0.6 (from 0.5). The GUI seems to expect RHD2000 usb-3.bit firmware, and not the one needed for our system, RHD2000. I think that the GUI is expecting GEN 2+, and this leads to issues, as I was unable to get the GUI to load  RHD2000, nor I was able to play with the  astconfig.xml to get this to work. 
What do you think?

Best,
Aviad

On Friday, June 27, 2025 at 10:30:02 AM UTC-7 Josh Siegle wrote:

Hi Aviad,

If you click the "ADC" button in the LFP Viewer (next to the "range" ComboBox), does that fix the problem? It's possible it's just a visualization issue.

Does the issue persist if you connect your signal to an alternative analog input channel? And have you tried recording the data to confirm that the offset shows up there as well?

Josh 

On Wed, Jun 18, 2025 at 12:39 PM, A-oz <ozana...@g.ucla.edu> wrote:

Hello everyone,

We have an Open Ephys Acquisition board and recently updated to the new GUI.

Since the update took place we are getting a distorted signal from analog outputs. 

We made sure it is not related to the eye tracker itself, by using a function generator and oscilloscope. Everything works as expected but the oscilloscope does not match what we see in the GUI (Please see attached. Signal in ADC 1 start higher than zero, shape are not representing the signal as they should and appear discretized).

We suspect it's a gain issue, the software seems to amplify the signal and discretize it. But can't find any where to define/change the gain for ADC 1.  We didn't had this issue in an older version of the software, so most likely it is not the  Acquisition board itself, which was working fine before. 

Best,
Aviad

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[A-oz]

Hi Josh,

I wrote a long comprehensive response and it disappear. Google platform is really annoying : /
Anyway, thank you again for your reply.
A shorter answer: We run all the checks and we are positive it is not the signal itself (channels, grounding issue, source issue - the same problem with the eye tracking, cables etc') , a visualization issue, or a gain issue. We think it's the way the signal is digitized. Note, that the signal we are inserting is smooth, we are getting a different shape. This is true across different frequency's and volt'. The matlab output is like that of the LPF not the oscilloscope. 

The reason is probably due to incompatibility between our gen 1 equ' board and the GUI, which might be expecting a gen 2+ board. First, the problem appeared after  we upgraded our system to win 11, and the software from 0.5x to 0.6x. Secondly, it seems that the software is  expecting a wrong firmware, RHD2000 USB-3.bit, and I seem to unable to load our RHD2000 bit. firmware. 
I tried to play with the lastconfig.xml, but was unable to solve that. 
Maybe or someone else can think of a different solution?

Thank you again. 
Best,
Aviad

On Friday, June 27, 2025 at 10:30:02 AM UTC-7 Josh Siegle wrote:

Hi Aviad,

If you click the "ADC" button in the LFP Viewer (next to the "range" ComboBox), does that fix the problem? It's possible it's just a visualization issue.

Does the issue persist if you connect your signal to an alternative analog input channel? And have you tried recording the data to confirm that the offset shows up there as well?

Josh 

On Wed, Jun 18, 2025 at 12:39 PM, A-oz <ozana...@g.ucla.edu> wrote:

Hello everyone,

We have an Open Ephys Acquisition board and recently updated to the new GUI.

Since the update took place we are getting a distorted signal from analog outputs. 

We made sure it is not related to the eye tracker itself, by using a function generator and oscilloscope. Everything works as expected but the oscilloscope does not match what we see in the GUI (Please see attached. Signal in ADC 1 start higher than zero, shape are not representing the signal as they should and appear discretized).

We suspect it's a gain issue, the software seems to amplify the signal and discretize it. But can't find any where to define/change the gain for ADC 1.  We didn't had this issue in an older version of the software, so most likely it is not the  Acquisition board itself, which was working fine before. 

Best,
Aviad

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[Josh Siegle]

Thanks for the additional info. It does sound like the software is not recognizing the board properly.

Can you launch the GUI with an empty signal chain, drop in the Acquisition Board plugin, copy the contents of the console into a text file, and attach it to your reply? That will help us troubleshoot what's going on.

Josh

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[A-oz]

Hi Josh, 

Thank you for your response.  I hope I haven't missed anything, this is after clearing the signal chain and adding a new acquisition board:

[open-ephys] Creating processor with name: Acquisition Board
---- Intan Technologies ---- Rhythm RHD2000 Controller v1.41 ----


FrontPanel DLL loaded.  Built: Nov 11 2016  13:08:03

Scanning USB for Opal Kelly devices...

Found 1 Opal Kelly device connected:
  Device #1: Opal Kelly XEM6310LX45 with serial number 2049000V66

Trying to open device with serial 2049000V66
Device opened
FPGA system clock: 0 MHz
Opal Kelly device firmware version: 1.30
Opal Kelly device serial number: 2049000V66
Opal Kelly device ID std::string: Opal Kelly XEM6310

Rhythm configuration file successfully loaded.  Rhythm version number: 1

Blocksize set to 1024
DDR burst set to 32



Best,
Aviad

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