Search found 954 matches

by Coen
Tue Jun 11, 2019 12:40 pm
Forum: BioSemi Software (ActiView executable)
Topic: Reviewing 30sec epochs of streaming data in ActiView
Replies: 2
Views: 274

Re: Reviewing 30sec epochs of streaming data in ActiView

1) Use the "Screen Lenght" selector in the lower left corner of ActiView (stop acquisition to change x-axis). 2) Use a BDF file reader (e.g. https://www.biosemi.com/download/ToolsForRuntimeEngine861/BDFreader-808.zip or http://www.teuniz.net/edfbrowser/) to view the history while the file is written...
by Coen
Mon Jun 03, 2019 12:44 pm
Forum: BioSemi Software (ActiView executable)
Topic: Recording specific EXG channels
Replies: 1
Views: 308

Re: Recording specific EXG channels

Use "free choice" channel selection to display the channels of interest in the monopolar display. In the file dialog, choose "save as monopolar displayed". Save the setting in a new CFG ("about" tabpage).

Unused channels do not affect used channels.

Best regards, Coen
by Coen
Mon Jun 03, 2019 12:41 pm
Forum: BioSemi all other topics
Topic: High voltage levels in EEG output
Replies: 3
Views: 395

Re: High voltage levels in EEG output

For the 24-bit data, use scaling LSB = 31.25 nV. Offsets up to 100 mV are normal.

Best regards, Coen (BioSemi)
by Coen
Mon Jun 03, 2019 12:39 pm
Forum: BioSemi Hardware
Topic: Delivering electric shocks while recording EEG
Replies: 3
Views: 392

Re: Delivering electric shocks while recording EEG

The software is deliberately designed to only save the unfiltered (bandwidth: DC to 1/5th of the sample rate) and unreferenced data.

Best regards, Coen (BioSemi)
by Coen
Wed May 29, 2019 5:49 pm
Forum: BioSemi all other topics
Topic: High voltage levels in EEG output
Replies: 3
Views: 395

Re: High voltage levels in EEG output

The data is DC: small EEG signals superimposed on large electrode offsets. Reject the offsets with a high-pass filter or baseline correction. Reference the data to reject large Common Mode, see https://www.biosemi.com/faq/cms&drl.htm --> http://www.biosemi.com/pics/zero_ref1_big.gif Best regards (Bi...
by Coen
Mon May 27, 2019 12:43 pm
Forum: BioSemi Hardware
Topic: Delivering electric shocks while recording EEG
Replies: 3
Views: 392

Re: Delivering electric shocks while recording EEG

Apparently, the simulator jeopardizes ActiveTwo's perfect galvanic isolation provided by battery power and fiber-optic data transfer. This causes high Common Mode (50/60 Hz interference on all channels). Reject Common Mode by referencing. The simulator is probably mains powered or connected to mains...
by Coen
Tue May 07, 2019 12:47 pm
Forum: EEG data analysis
Topic: slow drifting on EEG
Replies: 5
Views: 4800

Re: slow drifting on EEG

CMS, DRL and the reference electrode can all be on the mastoids. However, CMS in the cap (approx. in the center of the other electrodes) is theoretically a bit better (Common Mode more equally distributed among the electrodes). DRL can be anywhere on the body.

Best regards, Coen (BioSemi)
by Coen
Fri Apr 12, 2019 5:07 pm
Forum: BioSemi Hardware
Topic: Odd ~17Hz noise in all channels
Replies: 9
Views: 1616

Re: Odd ~17Hz noise in all channels

It is normal with the DRL on the head. It is caused by a small amount of 16 Hz excitation current flowing from the GSR electrodes to the DRL electrode. The 16 Hz leakage is minimal when the GSR electrodes have equal impedance and offset. However, this is difficult to check and control. The 16 Hz is ...
by Coen
Mon Apr 01, 2019 3:23 pm
Forum: BioSemi Software (ActiView executable)
Topic: Matlab TCP Connection
Replies: 4
Views: 1089

Re: Matlab TCP Connection

1) Both computers should be connected to the same network. The transmission speed does affect lag. 2) Select the "Sent local Port" in ActiView. Ounce the connection is established, ActiView displays the "Remote Display Port" with the same number. 3) Check the select box "Add 7 Sensors". RESP is the ...
by Coen
Fri Mar 22, 2019 1:08 pm
Forum: BioSemi Hardware
Topic: Fault with ActiveTwo AD Box
Replies: 4
Views: 778

Re: Fault with ActiveTwo AD Box

A gel bridge in the AD-box connector is the most likely cause.

Best regards, Coen (BioSemi)
by Coen
Fri Mar 22, 2019 12:26 pm
Forum: BioSemi Hardware
Topic: Pin Electrode Tip Broke Off
Replies: 1
Views: 742

Re: Pin Electrode Tip Broke Off

Pins break due to wear, aging and rough handling. Usually, performance is hardly affected (check noise in water). In case of a single broken pin, we can replace the active electrode (sent set to BioSemi). Replacing electrodes is generally not worthwhile on well used sets.

Best regards, Coen (BioSemi)
by Coen
Fri Mar 22, 2019 11:52 am
Forum: BioSemi Hardware
Topic: Fault with ActiveTwo AD Box
Replies: 4
Views: 778

Re: Fault with ActiveTwo AD Box

Dried gel is often invisible. Your top connector board needs to be replaced. Contact BioSemi for service and sent your AD-box.

Best regards, Coen (BioSemi)
by Coen
Mon Mar 04, 2019 1:26 pm
Forum: BioSemi Hardware
Topic: Odd ~17Hz noise in all channels
Replies: 9
Views: 1616

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: 2598

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: 759

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: 928

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: 1259

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: 906

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: 1259

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: 1259

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: 4
Views: 1089

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: 1080

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: 1080

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: 921

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: 1367

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: 1367

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: 1367

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: 1031

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: 1157

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: 1224

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 ...