Search found 965 matches

by Coen
Thu Sep 12, 2019 3:06 pm
Forum: ECG/EMG data analysis
Topic: offline heart rate extraction from ECG signal
Replies: 12
Views: 15235

Re: offline heart rate extraction from ECG signal

I would not agree with the above values because not much ECG information would be left in the outcome. Google on "ECG bandwidth" and you will find bandwidth recommendations in the order of 0.05-100 Hz (so at least 512 Hz sample rate). The LSB value used in the ActivTwo is publicized on https://www.b...
by Coen
Tue Aug 27, 2019 5:50 pm
Forum: BioSemi Software (ActiView executable)
Topic: Mssing Triggers
Replies: 12
Views: 386

Re: Mssing Triggers

Please sent the USB-receiver and trigger interface to BioSemi to check the hardware.

Best regards, Coen (BioSemi)
by Coen
Thu Aug 22, 2019 3:46 pm
Forum: BioSemi Software (ActiView executable)
Topic: Mssing Triggers
Replies: 12
Views: 386

Re: Mssing Triggers

Your trigger generation software seems OK: we see the triggers all perfectly in ActiView. Please confirm: did you (also) test with just the USB trigger interface connected to the USB-receiver ? So, without any other connection to the USB trigger interface (such as a splitter cable with connection to...
by Coen
Wed Aug 21, 2019 2:03 pm
Forum: BioSemi Software (ActiView executable)
Topic: Mssing Triggers
Replies: 12
Views: 386

Re: Mssing Triggers

Your tests prove that the BioSemi hard- and software is working correctly. Email you trigger generation program to info@biosemi.com.

Best regards, Coen (BioSemi)
by Coen
Mon Aug 19, 2019 3:12 pm
Forum: BioSemi Software (ActiView executable)
Topic: Mssing Triggers
Replies: 12
Views: 386

Re: Mssing Triggers

There might be a bad ground connection (pin 37). Check as follows:

Disconnect the USB cable from the USB-trigger interface. Plug just the USB-trigger interface (without USB-cable) into the USB-receiver and confirm that all triggers 1-16 change from HIGH to LOW.

Best regards, Coen (BioSemi)
by Coen
Fri Aug 16, 2019 1:57 pm
Forum: BioSemi Software (ActiView executable)
Topic: Mssing Triggers
Replies: 12
Views: 386

Re: Mssing Triggers

The blackbox toolkit (BBTK) system has a 25-pole TTL input connector. Did you actually make a 37 to 25 parallel cable ? Test the trigger port on the USB-receiver as described in post 4 in http://www.biosemi.nl/forum/viewtopic.php?f=1&p=3615#p3615 (short pin 1-16 to pin 37). If the port responds OK, ...
by Coen
Tue Aug 13, 2019 5:28 pm
Forum: BioSemi Software (ActiView executable)
Topic: Mssing Triggers
Replies: 12
Views: 386

Re: Mssing Triggers

How did you establish that you are actually sending triggers when you do not see them in ActiView ?

Best regards, Coen (BioSemi)
by Coen
Tue Aug 13, 2019 1:41 pm
Forum: BioSemi Hardware
Topic: Random '20202020...' triggers
Replies: 6
Views: 1973

Re: Random '20202020...' triggers

If 9 and 10 are not continuously high with detached cable, then the RespSwitch setting in the used CFG is still on "1", change it to "0". You state that all other trigger lines are high, but the picture shows line 16 low. Probably a hardware problem, but unrelated to the 9 and 10 behavior. You can i...
by Coen
Fri Aug 09, 2019 2:12 pm
Forum: BioSemi Hardware
Topic: Random '20202020...' triggers
Replies: 6
Views: 1973

Re: Random '20202020...' triggers

Disconnect the trigger cable from the USB-receiver. All trigger lines should now be high (if 9 and/or 10 are low, then there is still a wrong setting in the CFG). Then short pin 10 to pin 37. This should pull line 10 low (also compare with other lines). If line 10 does not respond, then sent the USB...
by Coen
Thu Aug 01, 2019 3:43 pm
Forum: BioSemi Software (ActiView executable)
Topic: Trigger Codes Missing Sporadically
Replies: 2
Views: 303

Re: Trigger Codes Missing Sporadically

1) Set the trigger format (lower left corner) to "analog" to troubleshoot. You can then identify 16 separate lines (bits). Colored dots/bars indicate a that a line is HIGH. grey background indicate that a line is LOW. 2) Use positive logic: HIGH is trigger. LOW is idle (with negative logic, triggers...
by Coen
Tue Jul 30, 2019 2:42 pm
Forum: EEG data analysis
Topic: merging BDFs?
Replies: 10
Views: 18909

Re: merging BDFs?

Install RTE 8.6 (http://ftp.ni.com/support/softlib/labview/labview_runtime/8.6.1/Windows/LVRTE861STD.exe) and run the merger86.exe Press "START", select the first and second BDF files from the successive popping up file dialogs, type the target file name in the third popup file dialog, and the merge...
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: 597

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: 615

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: 761

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: 718

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: 761

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: 718

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: 5305

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: 2046

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: 1442

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: 1138

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: 1048

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: 1138

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: 2046

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: 2965

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: 1075

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: 1284

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: 1679

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: 1224

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: 1679

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...