Search found 942 matches

by Coen
Mon Mar 04, 2019 1:26 pm
Forum: BioSemi Hardware
Topic: Odd ~17Hz noise in all channels
Replies: 7
Views: 658

Re: Odd ~17Hz noise in all channels

Interference by GSR is usually Common Mode, and can be reduced substantially by referencing (which should always applied anyway before analysis). However, in a FFT over a lot of points, the 16 Hz peak will of course eventual always show up, this is normal. Ensure a good (equal) electrode contact of ...
by Coen
Tue Feb 26, 2019 4:07 pm
Forum: BioSemi Hardware
Topic: Problem with 32 channel headbox / EKG
Replies: 6
Views: 1808

Re: Problem with 32 channel headbox / EKG

>Question 1 : >I think Amp / ADC modules are not installed on the C channels. >Could you please explain me how to do it (level : beginner) ? See my earlier post in this thread about hwo to check which channels are installed. Contact BioSemi directly for purchase and installation of more channels. >Q...
by Coen
Mon Feb 25, 2019 12:53 pm
Forum: BioSemi all other topics
Topic: ECG using Flat Active electrodes
Replies: 1
Views: 126

Re: ECG using Flat Active electrodes

An option is to measure ECG between the arms, search the web for "Einthoven lead I".

Best regrads, Coen (BioSemi)
by Coen
Sun Feb 24, 2019 10:59 pm
Forum: BioSemi all other topics
Topic: Differences between decimater utility and Python
Replies: 3
Views: 159

Re: Differences between decimater utility and Python

The decimator tool does just apply a 5th order cascaded integrator-comb (CIC) filter, no extra filtering/smoothing. Inspect the (open-source) LabVIEW code for confirmation.

Best regards, Coen (BioSemi)
by Coen
Thu Feb 14, 2019 1:10 pm
Forum: BioSemi all other topics
Topic: Missing triggers and data
Replies: 6
Views: 331

Re: Missing triggers and data

> 1. Why were these channels recorded in the first place? What did I need to do for them not be recorded? Use the proper setting in the ActiView file dialog. I assume you use 4 EX channels for EMG. 1) Select to only display the 4 EMG channels in the monopolar display (use Channel selection option "f...
by Coen
Mon Feb 11, 2019 4:22 pm
Forum: BioSemi Software (ActiView executable)
Topic: ActiView cfg file format documentation
Replies: 1
Views: 218

Re: ActiView cfg file format documentation

The CFG is meant to be edited from ActiView. Just a few entries should be edited directly (e.g. with Notepad or Wordpad). For more info, see viewtopic.php?f=2&t=7&p=2232

Best regards, Coen (BioSemi)
by Coen
Tue Feb 05, 2019 3:15 pm
Forum: BioSemi all other topics
Topic: Missing triggers and data
Replies: 6
Views: 331

Re: Missing triggers and data

All I know about Analyzer is that it was updated with a total BDF blockade as far back as 2003 (after working perfectly between 2000 and 2003). Since then, all relevant publications from the vendor list the statement "BioSemi not supported". Not surprisingly, most of the BioSemi customers were quite...
by Coen
Mon Feb 04, 2019 3:21 pm
Forum: BioSemi all other topics
Topic: Missing triggers and data
Replies: 6
Views: 331

Re: Missing triggers and data

Do you see the same data corruption in ActiView during recording ?

Do you see the same result in alternative BDF file readers such as https://www.biosemi.com/download/ToolsF ... er-808.zip and http://www.teuniz.net/edfbrowser/ ?

Best regards, Coen (BioSemi)
by Coen
Mon Feb 04, 2019 3:15 pm
Forum: BioSemi Software (ActiView executable)
Topic: Matlab TCP Connection
Replies: 2
Views: 255

Re: Matlab TCP Connection

TCP connection is not available on all speedmodes. If the TCP tab is greyed-out during running, then you are using a speedmode where TCP is unavailable (multibox, AIB). Test with speedmode 4,5,6 or 7. Also see viewtopic.php?f=2&t=413&p=3007

Best regards, Coen (BioSemi)
by Coen
Fri Feb 01, 2019 12:35 pm
Forum: BioSemi all other topics
Topic: ecg
Replies: 6
Views: 315

Re: ecg

Order "CMS/DRL Flat Set" (EUR 100 excl. shipping). First check that your AD-box has a CMS/DRL connection on the front-panel (there should be a CMS/DRL label above the most left DIN connector). If not, order "CMS/DRL Flat Set SCSI".

Best regards, Coen (BioSemi)
by Coen
Thu Jan 31, 2019 2:43 pm
Forum: BioSemi all other topics
Topic: ecg
Replies: 6
Views: 315

Re: ecg

CMS/DRL is required for any electrode measurement. When not using the headcap, use a seperate (flat) CMS/DRL connected to the front-panel of the AD-box.

Best regards, Coen (BioSemi)
by Coen
Fri Jan 25, 2019 3:17 pm
Forum: BioSemi Hardware
Topic: Trigger inputs through USB receiver
Replies: 1
Views: 254

Re: Trigger inputs through USB receiver

> My question is will the actiview software detect the trigger signal when pin1 goes to 5V.

Yes.


> I believe biosemi recognizes that the trigger pins are 'active high' when there is no input. should i ground the other trigger pins?

Not necessary.

Best regards, Coen (BioSemi)
by Coen
Tue Jan 22, 2019 4:07 pm
Forum: BioSemi Software (ActiView executable)
Topic: Trigger code oddities
Replies: 6
Views: 467

Re: Trigger code oddities

As instructed above, use "analog" trigger display mode to see which bits (besides LSB for 0 -->1) are switching.

Best regards, Coen (BioSemi)
by Coen
Sat Jan 19, 2019 10:26 am
Forum: BioSemi Software (ActiView executable)
Topic: Trigger code oddities
Replies: 6
Views: 467

Re: Trigger code oddities

Values are listed in the post link given above. Return to 0 after each trigger.

Bets regards, Coen (BioSemi)
by Coen
Mon Jan 14, 2019 3:09 pm
Forum: BioSemi Software (ActiView executable)
Topic: Trigger code oddities
Replies: 6
Views: 467

Re: Trigger code oddities

Instead of 0 --> 255 -->0 , your code probably generates 0 --->255 ---> 254 ---> 0 0 = 00000000 254 = 11111110 255 = 11111111 The 8 bits do not return to 0 simultaneously. Solution: toggle only one bit per trigger event, see http://www.biosemi.nl/forum/viewtopic.php?f=7&t=1022 In general: always use...
by Coen
Thu Jan 10, 2019 1:09 pm
Forum: BioSemi Hardware
Topic: Error 5000
Replies: 1
Views: 358

Re: Error 5000

Common causes of intermittent 5000 errors are (ordered from most to least likely): - bad optical fiber - bad USB cable - bad optical transmitter - bad optical receiver Replace fiber and USB cable. If the problem persists, then sent the AD-box and USB receiver to BioSemi for testing and repair. Best ...
by Coen
Fri Jan 04, 2019 1:04 pm
Forum: BioSemi Hardware
Topic: Error 5000
Replies: 1
Views: 463

Re: Error 5000

Use the registry cleaning tool to remove the manually installed driver, see https://www.biosemi.com/faq/install_USB.htm

Do not install the driver manually under W10, just plug in the USB-Receiver and the driver will install automatically.

Best regards, Coen (BioSemi)
by Coen
Tue Dec 18, 2018 2:46 pm
Forum: BioSemi all other topics
Topic: Calculating CMS & DRL Values
Replies: 2
Views: 512

Re: Calculating CMS & DRL Values

The data stream consists of measured voltages. A voltage is a difference in potential. In case of the ActiveTwo, the electrode potentials are measured with respect to the potential of a point between the CMS and DRL electrodes, see http://www.biosemi.nl/forum/viewtopic.php?f=1&t=177&p=391 . You are ...
by Coen
Wed Dec 12, 2018 1:36 pm
Forum: BioSemi Hardware
Topic: Odd ~17Hz noise in all channels
Replies: 7
Views: 658

Re: Odd ~17Hz noise in all channels

Is GSR used and connected to the subject ?

Is the interference seen in the bucket test (without GSR electrodes) ?

Best regards, Coen (BioSemi)
by Coen
Wed Nov 28, 2018 12:42 pm
Forum: BioSemi all other topics
Topic: Trigger error in low sample rate
Replies: 1
Views: 589

Re: Trigger error in low sample rate

Use positive trigger logic (down-sampling uses OR function to calculate trigger of multiple samples)
Use "analog" trigger display to investigate the problem.

see viewtopic.php?f=7&t=1022

Best regards, Coen (BioSemi)
by Coen
Tue Nov 27, 2018 5:13 pm
Forum: BioSemi Hardware
Topic: Custom electrodes for EXG channel
Replies: 1
Views: 636

Re: Custom electrodes for EXG channel

BioSemi treats the schematics as proprietary information, they are not shared with anyone outside the company.

Best regards, Coen (BioSemi)
by Coen
Mon Nov 05, 2018 3:13 pm
Forum: EEG data analysis
Topic: Impact of reference electrode for import on data ?
Replies: 3
Views: 861

Re: Impact of reference electrode for import on data ?

It does not matter. A reference far away generates high Common Mode voltages, a reference close to the area of interest generates small signal amplitudes. Re-referencing cancels these effects.

Best regards, Coen (BioSemi)
by Coen
Fri Nov 02, 2018 12:49 pm
Forum: EEG data analysis
Topic: Impact of reference electrode for import on data ?
Replies: 3
Views: 861

Re: Impact of reference electrode for import on data ?

A voltage is a difference in potential. So, the choice of reference does of course affect the eventual EEG voltages. The choice during import does not affect later alternative choices of the reference.

Best regards, Coen (BioSemi)
by Coen
Thu Nov 01, 2018 7:15 pm
Forum: BioSemi Software (ActiView executable)
Topic: modify STRIDE value for use with Matlab API
Replies: 1
Views: 768

Re: modify STRIDE value for use with Matlab API

The default Stride is set at approx. 60 milliseconds. If your ("huge") delays are much larger than this value, then the bottle-neck lies elsewhere (ActiView, TCP/IP transfer, PC processing speeds, etc.). Stride can be adjusted by calling functions in the Labview_DLL.dll: OPEN_DRIVER_ASYNC --> BSIF_S...
by Coen
Wed Oct 31, 2018 4:24 pm
Forum: BioSemi Software (ActiView executable)
Topic: Sending Frequency of data from TCP/IP
Replies: 7
Views: 1044

Re: Sending Frequency of data from TCP/IP

Your approach will work, providing that the value generated by ActiView divided by the value you select manually is an integer. For example: if ActiView generates a value of 16 samples/chan, the you can manually set 1, 2, 4 or 8 samples/chan.

Best regards, Coen (BioSemi)
by Coen
Fri Oct 26, 2018 12:59 pm
Forum: BioSemi Hardware
Topic: Random '20202020...' triggers
Replies: 1
Views: 808

Re: Random '20202020...' triggers

viewtopic.php?f=7&t=977&p=2985

Best regards, Coen (BioSemi)
by Coen
Wed Oct 24, 2018 12:19 pm
Forum: EEG data analysis
Topic: Inconsistencies with channel locations
Replies: 6
Views: 1226

Re: Inconsistencies with channel locations

Geographic coordinates (EEGLab) have now been added to the position file, see https://www.biosemi.com/download/Cap_coords_all.xls

Best regards, Coen (BioSemi)
by Coen
Mon Oct 22, 2018 11:44 am
Forum: BioSemi Software (ActiView executable)
Topic: Sending Frequency of data from TCP/IP
Replies: 7
Views: 1044

Re: Sending Frequency of data from TCP/IP

The TCP_samples/channel is generated in ActiView and linked to the packet size that is used to read the ringbuffer and the minimum step size for scrolling the data on screen. You can change only the value by editing the (open-source) LabVIEW code of ActiView (LabVIEW programming environment required...
by Coen
Mon Oct 15, 2018 1:55 pm
Forum: BioSemi Software (ActiView executable)
Topic: Sending Frequency of data from TCP/IP
Replies: 7
Views: 1044

Re: Sending Frequency of data from TCP/IP

The data is buffered (in the ringbuffer and in ActiView and in the TCP/IP protocol) so the sending rate over TCP/IP fluctuates.

Collect 4096 samples in your receive program, and you have exact 2 seconds of data.

Best regards, Coen (BioSemi)
by Coen
Thu Oct 04, 2018 4:16 pm
Forum: EEG data analysis
Topic: Inconsistencies with channel locations
Replies: 6
Views: 1226

Re: Inconsistencies with channel locations

Basically, we use the ISO spherical system (https://en.wikipedia.org/wiki/Spherical_coordinate_system) whereas EEGLAB uses coordinates based on the geograpic system (https://en.wikipedia.org/wiki/Geographic_coordinate_system). The relation between the two systems is a bijection (one-to-one correspon...