BioSemi.nl

24-bit data. little endian, with LSB = 31.25 nV. Signals are DC, so uV EEG superimposed on tens of mV offset (apply high-pass filter to cancel offsets).

Best regards, Coen (BioSemi)

No need to hook up a subject: 1) Use "one bucket" method (see manual), make waves in the data by shaking the bucket. 2) Use "two bucket" method and use a signal generator with passive Ag-AgCl electrodes in the buckets. 3) If you have an AIB: select speedmode 4, 5, 6 or 7 and connect a signal generat...

1) Yes, GSR processing has not changed 2) Yes, RESP and PLETH are in uV, but not calibrated. 3) First step is a little different: Signal1 = double(Non_inverting_Temp+2^30) - (Inverting_Temp-2^30) If I remember correctly (it's 20 years ago) the signal (Non_Inverting_Temp - Inverting_Temp) could overf...

Any USB cable is OK, also try a different USB port.

Best regards, Coen (BioSemi)

1) Higher Common Mode
2) WCT reference offers standardized ECG waveforms

Best regards, Coen (BioSemi)

1) For ECG, locate CMS on the chest. DRL can be anywhere on the body. 2) For hearttrate determination, just use two electrodes on the chest and process the difference (E1 -E2) in your BDF file reader. 3) Bipolar displayed signals are just differences between two raw channels (not affected by referen...

Accurate timing is only possible by supplying timestamps to the trigger port on the USB receiver (triggers are sampled synchronously with the EEG data).

Best regards, Coen (BioSemi)

> I do not expect to be told to go to Google to get technical details about how to send markers. I direct you again to Google on the basic issue of how to split a 16 bit word into two 8 bit bytes during processing of the BDF file. This has nothing to do with sending triggers to the USB-receiver, For...

> I am still unsure as to why we have correct trigger codes when I use the decimal settings in ActiView, but then different ones in the .bdf file? Because for the ActiView display in "decimal" mode, the 16 bit trigger codes (see https://www.biosemi.com/faq/trigger_signals.htm and ) are split into tw...

Split the 16 bit trigger word in two 8 bit bytes. ActiView does not affect the codes saved in the BDF file.

Best regards, Coen (BioSemi)

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...

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

Best regards, Coen (BioSemi)

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...

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)

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)

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, ...

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

Best regards, Coen (BioSemi)

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...

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...

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...

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...

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...

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

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

Best regards, Coen (BioSemi)

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)

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...

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...

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)

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 ...

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 ...