Search found 1125 matches
- Wed May 27, 2009 2:54 pm
- Forum: BioSemi Hardware
- Topic: high correletaion of data in salt water?
- Replies: 2
- Views: 6373
Did you use the unreferenced (raw) signals as basis of your analysis ? The correlation is a measure for the amount of Common Mode in the signals. The CMS/DRL loop becomes less effective at higher frequencies (the loop amplification decreases proportionally to the frequency). So, it is to be expected...
- Tue May 26, 2009 5:10 pm
- Forum: BioSemi Software (LabVIEW programming)
- Topic: regarding USB_WRITE function in labview_dll.dll
- Replies: 6
- Views: 23260
The program reads (variable) parts of the ringbuffer. The data remains available in the ringbuffer until overwritten by new data (when the "clock" has made a full round). The convertxxx vi's are used to adjust the program to the version (Mk1 or Mk2) and sample rate (speedmode) of the connected AD-bo...
- Fri May 22, 2009 2:48 pm
- Forum: BioSemi Software (LabVIEW programming)
- Topic: regarding USB_WRITE function in labview_dll.dll
- Replies: 6
- Views: 23260
- Fri May 22, 2009 1:45 pm
- Forum: BioSemi Software (LabVIEW programming)
- Topic: regarding USB_WRITE function in labview_dll.dll
- Replies: 6
- Views: 23260
The USB_WRITE call is used for two functions: - start and stop acquisition, 1st byte of the 64 byte array is used, in LabVIEW, I used the values 1 and 0 to start/stop the acquisition (actually, only the LSB of the byte is read by the USB receiver to start and stop) - sent output triggers to the trig...
- Thu May 21, 2009 3:58 pm
- Forum: EEG data analysis
- Topic: Error 6004: File Size in Header
- Replies: 1
- Views: 6083
The usual cause for a wrong file size in the header is that the recording was not stopped normally (but instead by a PC crash, full harddisk, etc.). If the file is basically correct, and the problem is just in the header, then you can repair the file with the tool available from http://www.biosemi.c...
- Tue May 19, 2009 1:23 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: error 5000 remains
- Replies: 4
- Views: 8385
- Tue May 19, 2009 12:42 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: error 5000 remains
- Replies: 4
- Views: 8385
f nothing has been changed to the PC and AD-box (speedmode ?), then the USB cable and optical cable are the prime suspects. - Is the "optical link" light on the USB receiver on to indicate that data is received ? - What happens with the "USB link" light on the receiver when acquisition is started ? ...
- Mon May 18, 2009 3:00 pm
- Forum: BioSemi all other topics
- Topic: Standard BioSemi PArallel Port Cable Incompatibility
- Replies: 12
- Views: 16445
As far as I know, the basic ActiView code can be used. However, the problem with LabVIEW RT is that it needs to run on dedicated real time (National Instruments) hardware. An interface between the ActiveTwo and this special real time hardware is not available at the moment. An option (using our stan...
- Mon May 18, 2009 12:55 pm
- Forum: BioSemi all other topics
- Topic: Standard BioSemi PArallel Port Cable Incompatibility
- Replies: 12
- Views: 16445
A new version of the zip file (same name, now 3.7 Mb) is available on the same link as above, the full source code is now added to the zip. Follow the "Triggers Boolean" output array from subvi "TrigProcess.vi", and you'll find an added USB_WRITE function call (lower right section of the main diagra...
- Thu May 14, 2009 3:56 pm
- Forum: BioSemi Hardware
- Topic: Measuring with 2 different electrode sets
- Replies: 2
- Views: 6262
Old electrodes may produce more (low frequency) noise than newer ones. Electrode wear cannot significantly influence signal amplitude. You can easily check this with a "two bucket test", as described in the guidelines for use of the ActiveTwo system. In other words: you may encounter differences in ...
- Wed May 13, 2009 2:19 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: heartrate measure
- Replies: 1
- Views: 5199
- Tue May 12, 2009 3:25 pm
- Forum: BioSemi Hardware
- Topic: Re-referencing and MMN/N400
- Replies: 3
- Views: 7519
I don't know an "official" coordinate. However, the coordinates of the nose can be quite easily extrapolated from the existing ones. The azimuth is surely 90 degrees (same as Fpz, Fz, etc), the inclination should be something around 138 degrees (Fpz is on 92, arc length from nose to Fpz is approx eq...
- Mon May 04, 2009 1:24 pm
- Forum: BioSemi all other topics
- Topic: Standard BioSemi PArallel Port Cable Incompatibility
- Replies: 12
- Views: 16445
A special version of ActiView is ready for download from http://www.biosemi.com/download/ActiView606-Lores.zip . This version routes the response signals from input trigger lines 9 and 10 to trigger output lines 1 and 2 (pin 17 and 18, see http://www.biosemi.com/faq/trigger_signals.htm). Please note...
- Mon Apr 27, 2009 7:59 pm
- Forum: EEG data analysis
- Topic: Suspicious about the electrode locations file
- Replies: 1
- Views: 5888
- Mon Apr 20, 2009 4:03 pm
- Forum: BioSemi all other topics
- Topic: Standard BioSemi PArallel Port Cable Incompatibility
- Replies: 12
- Views: 16445
- Mon Apr 20, 2009 3:09 pm
- Forum: BioSemi all other topics
- Topic: Standard BioSemi PArallel Port Cable Incompatibility
- Replies: 12
- Views: 16445
- Mon Apr 20, 2009 2:19 pm
- Forum: BioSemi all other topics
- Topic: Standard BioSemi PArallel Port Cable Incompatibility
- Replies: 12
- Views: 16445
The LabVIEW code of ActiView Light (http://www.biosemi.com/download/ActiView604-Light.zip) shows an example of how to sent codes to trigger port (15 lines available). You will have to make the appropriate cable yourself according to the information on http://www.biosemi.com/faq/trigger_signals.htm B...
- Tue Apr 07, 2009 1:32 pm
- Forum: BioSemi Hardware
- Topic: Strange looking drifts through all channels
- Replies: 5
- Views: 9776
When water or gel enters the electrode, they will stop working, and they won't work again (blue light keeps blinking). Problems with leaking electrode have never been reported to us. A possible cause is pollution of the Ag-AgCl tips with traces of non-silver metal. However, the low frequency noise w...
- Tue Apr 07, 2009 11:45 am
- Forum: BioSemi Hardware
- Topic: Strange looking drifts through all channels
- Replies: 5
- Views: 9776
The artefacts in your file ("bump" on most channels from t=76 to t=80) look like slow waves due to sweating, as discussed in thread viewtopic.php?t=28.
Best regards, Coen (BioSemi)
Best regards, Coen (BioSemi)
- Mon Apr 06, 2009 12:29 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: TTL Pulse width recognition
- Replies: 3
- Views: 8686
- Wed Mar 25, 2009 3:09 pm
- Forum: BioSemi Hardware
- Topic: recording only external (eye) electrodes
- Replies: 3
- Views: 6816
- Wed Mar 25, 2009 3:03 pm
- Forum: BioSemi Hardware
- Topic: Re-referencing and MMN/N400
- Replies: 3
- Views: 7519
In general, you can check your referencing step because the reference trace should be flat after referencing (everything zero, no noise). In your example, the EXG5 trace should be flat after referencing all channels to EXG5. The CMS/DRL loop cancels out after referencing In general, the reference ch...
- Fri Mar 13, 2009 5:25 pm
- Forum: BioSemi Hardware
- Topic: recording only external (eye) electrodes
- Replies: 3
- Views: 6816
A ringbuffer overflow means that the PC is not able to keep up with the incoming data stream. Basically, the problem can only be solved with a faster processor in your acquisition PC A CMS and DRL electrodes is always necessary, also if you only use the flat electrodes (EX inputs). The ringbuffer ov...
- Fri Mar 06, 2009 11:16 am
- Forum: BioSemi Hardware
- Topic: Diagnose a Broken Electrode (with pictures!)?
- Replies: 4
- Views: 10603
The signal trace suggest a bad contact between electrode tip and skin (not enough gel in the holder). The electrode itself is most probably OK. A defect electrode (broken wire) will trigger the safety circuits, and signal on all electrodes will be lost (blue light flickering). Another possibility is...
- Wed Mar 04, 2009 12:30 pm
- Forum: BioSemi Hardware
- Topic: usb reciever output
- Replies: 1
- Views: 5231
With the Jazz enabled (output trigger is 16 High), the special Jazz version of the USB receiver adds 4 extra channels to the data stream. Inspect the LabVIEW code of the subvi named Act_Jazz.vi to learn about how the Jazz information is embedded in the 4 extra channels (it's quite complex). With the...
- Fri Feb 27, 2009 2:57 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: Additional Trigger Question
- Replies: 6
- Views: 12397
The trigger cables as currently delivered by BioSemi already have triggers 9-16 grounded (connected to pin 37). This is not true for our older cables (delivered before 2007), were triggers 9-16 are floating (and pulled high by the pull-ups in the receiver). The change of the 24-bit value in the firs...
- Thu Feb 19, 2009 5:36 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: Additional Trigger Question
- Replies: 6
- Views: 12397
The connection of pin 9-16 to pin 37 is indeed done by soldering a short wire. The pin layout can for example be found on http://pinouts.ru/connector/37_pin_D-SU ... ctor.shtml (pin 1 is also seen inside the connector).
Best regards, Coen (BioSemi)
Best regards, Coen (BioSemi)
- Fri Feb 13, 2009 12:01 pm
- Forum: BioSemi Hardware
- Topic: optic fiber cable
- Replies: 3
- Views: 7508
- Fri Feb 06, 2009 2:38 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: BDF Record Length
- Replies: 2
- Views: 6306
- Tue Feb 03, 2009 4:37 pm
- Forum: BioSemi Hardware
- Topic: AD-box problem
- Replies: 2
- Views: 5991