Please read the forum and our website, and stop poluting this forum with silly questions.
Regards, Coen (BioSemi)
Search found 1124 matches
- Mon Nov 20, 2006 11:52 am
- Forum: BioSemi all other topics
- Topic: principle of functionning
- Replies: 2
- Views: 8074
- Wed Nov 01, 2006 8:18 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: Additional Trigger Question
- Replies: 6
- Views: 12331
On ActiView 5.14 and higher, the function keys F1-F8 are by standard coupled to trigger lines 9-16. A key press makes the respective trigger line high. Make sure that the trigger inputs 9-16 are pulled low at the trigger port of the USB receiver (by connecting pin 9-16 to pin 37). If trigger inputs ...
- Fri Oct 27, 2006 4:21 pm
- Forum: EEG data analysis
- Topic: Trigger problems revisited
- Replies: 3
- Views: 11319
- Thu Oct 05, 2006 12:57 pm
- Forum: BioSemi Hardware
- Topic: Trigger with parallel port
- Replies: 1
- Views: 5577
You can sent the TTL (0-5V) signals from the parallel port directly to the input pins (pin 1-16) of the trigger port on the USB receiver. Make the ground connection by connecting pin 25 on the parallel port to pin 37 on the trigger port on the USB receiver (see http://www.biosemi.com/faq/trigger_sig...
- Wed Sep 27, 2006 3:57 pm
- Forum: BioSemi Hardware
- Topic: passive electrodes
- Replies: 4
- Views: 9098
I assumed an EIT setup with passive electrodes to inject current, and a separate set of active electrodes to measure the resulting potential distribution. You are correct that our active electrodes cannot be used for current injection. The ActiveTwo inputs can be modified to work with (any) passive ...
- Tue Sep 26, 2006 10:54 am
- Forum: BioSemi Hardware
- Topic: passive electrodes
- Replies: 4
- Views: 9098
- Mon Sep 25, 2006 10:38 pm
- Forum: BioSemi Software (LabVIEW programming)
- Topic: Modifying actiview program: Changing the screen resolution
- Replies: 9
- Views: 21278
- Mon Sep 25, 2006 5:47 pm
- Forum: BioSemi Software (LabVIEW programming)
- Topic: Modifying actiview program: Changing the screen resolution
- Replies: 9
- Views: 21278
- Mon Sep 25, 2006 4:53 pm
- Forum: BioSemi Software (LabVIEW programming)
- Topic: Modifying actiview program: Changing the screen resolution
- Replies: 9
- Views: 21278
- Mon Sep 18, 2006 1:10 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: Timing accuracy of USB trigger out
- Replies: 8
- Views: 16642
The "data" input of USB_WRITE is an array of 64 Bytes. The first Byte is used to start/stop the acquisition (00=stop, FF= start). The second and third byte are used to control the outgoing triggers (example: 01 + 00 makes pin 17 High, and 18-31 Low ). The remaining 61 bytes are not used. Best regard...
- Thu Sep 07, 2006 3:54 pm
- Forum: BioSemi Software (LabVIEW programming)
- Topic: Modifying actiview program: Changing the screen resolution
- Replies: 9
- Views: 21278
You cannot modify the exe directly. You'll need to have the LabVIEW programming environment installed on your PC (LabVIEW full development version). Open the ActiView LabVIEW library (ActiviewXXX.llb). It is then basically a matter of resizing all front panel controls and indicators. In addition, yo...
- Thu Aug 24, 2006 8:40 am
- Forum: BioSemi Software (ActiView executable)
- Topic: No reference or average reference?
- Replies: 3
- Views: 13859
Dear John, On March 11th, 2004, I have sent the following personal email to to you: [quote]To record 32 pin and 3 EX channels, proceed as follows: 1) In the monopolar tabpage, select channel selection "free choice" 2) In the channels list, select channels 1-32 and EX1, EX2 and EX3, there are now 35 ...
- Tue Aug 15, 2006 3:01 pm
- Forum: BioSemi Hardware
- Topic: EEG trigger- rising edge or falling edge?
- Replies: 1
- Views: 6684
ActiView displays both the rising and falling edges of the triggers. It is instructive to compare the "analog" and "decimal" display formats while the system is running. The recording of triggers in the BDF file is level sensitive, not edge sensitive. For example, bit 0 of the trigger/status channel...
- Fri Aug 11, 2006 10:55 am
- Forum: BioSemi Software (LabVIEW programming)
- Topic: how to read filtered signals from BDF reader to Matlab
- Replies: 1
- Views: 10893
- Wed Aug 09, 2006 1:27 pm
- Forum: BioSemi Hardware
- Topic: Power / CMS in range going off
- Replies: 1
- Views: 5497
Besides the current limiter in the DRL circuit (which switches off the power supply to the active electrodes is larger then normal leakage currents are detected), the ActiveTwo has a secondary safety circuit which switches off the entire AD-box if faulty voltage levels are detected on the internal s...
- Thu Aug 03, 2006 11:13 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: ignoiring channels while recording
- Replies: 1
- Views: 5784
- Thu Aug 03, 2006 11:07 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: data compression mechanism
- Replies: 3
- Views: 8331
If you run BDF-todecimatedBDF.exe: make sure you have the LabVIEW run-time-engine version 7.1 properly installed (RTE is freeware, available from ftp://ftp.ni.com/support/labview/windows/runtime/7.1/LVRunTimeEng.exe) If you run BDF-todecimatedBDF.llb: make sure you have LabVIEW 7.1 or higher install...
- Thu Aug 03, 2006 5:12 pm
- Forum: BioSemi Hardware
- Topic: Charger
- Replies: 1
- Views: 5432
The symptoms suggest that there is no power available at the output connector of the wall-adapter. Check with a voltmeter, there should be 9V between the concentric plug poles. No 9V: make sure that the wall outlet is OK (between 100 and 240 VAC). If it is, please sent the wall-adapter to BioSemi fo...
- Thu Aug 03, 2006 4:07 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: data compression mechanism
- Replies: 3
- Views: 8331
The data can be re-sampled to a lower sample rate with the Decimator tool from http://www.biosemi.com/download/BDF-to-decimatedBDF.zip . You will of course reduce the bandwidth of the data (new -3 dB point is at 0.2616 multiplied by the new sample rate), so use the tool wisely. Compression tools lik...
- Thu Jul 20, 2006 6:18 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: ActiView finite or continuous acquisition?
- Replies: 1
- Views: 5893
ActiView certainly supports continuous acquisition of data ActiView reads new data out of the ringbuffer with subvi Act_ring.vi, whether new data is available is decided on the basis of the READ_POINTER function call, and subsequent calculations in subvi Act_Pointer.vi (all within the acquisition Wh...
- Tue Jul 04, 2006 5:00 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: Actiview components
- Replies: 3
- Views: 12206
A trimmed down version in LabVIEW 8.2 is now available from http://www.biosemi.com/download/ActiView603-Light.zip
Best regards, Coen (BioSemi)
Best regards, Coen (BioSemi)
- Fri Jun 23, 2006 12:53 pm
- Forum: EEG data analysis
- Topic: Reference and averaging
- Replies: 1
- Views: 6890
So long as you do not perform any artifact rejection, it does not matter whether the referring is done before or after averaging. However, performing artifact rejection on unreferenced (raw) signals will lead to wrong results. So, in practice you should always reference (and filter) the data before ...
- Thu Jun 01, 2006 2:51 pm
- Forum: BioSemi Hardware
- Topic: Shielding in EEG
- Replies: 8
- Views: 21763
IMRR: apply test signal with known voltage across the isolation barrier, and measure the effect on the system's output signal (see http://www.biosemi.com/publications/pdf/Isolation_mode_rejection.pdf) Isolation capacitance: apply (AC) test signal with known voltage across the isolation barrier, and ...
- Thu May 25, 2006 9:43 pm
- Forum: BioSemi Hardware
- Topic: Shielding in EEG
- Replies: 8
- Views: 21763
What exactly do you want to measure: the Isolation Mode Rejection Ratio (IMRR), the isolation capacitance, the breakdown voltage of the isolation, or some other parameter ? If you want to contribute to this forum, I would appreciate it if you would at least put some effort into writing a clear quest...
- Tue Apr 18, 2006 11:08 pm
- Forum: BioSemi Hardware
- Topic: Electrode Noise Levels
- Replies: 3
- Views: 9504
When measured with the electrodes in saline (salt water), the electrode noise is very close to the noise level of the electronic circuitry (a few microvolt peak-to-peak, see specs). Please explain how you have determined the electrode noise when measuring on a subject skin. In other words: which met...
- Thu Apr 13, 2006 1:15 pm
- Forum: BioSemi Software (ActiView executable)
- Topic: problem recording data from EXG electrodes while using AIB
- Replies: 2
- Views: 8311
This is not a known bug. Please test with the latest 5.37 version of ActiView (http://www.biosemi.com/download.htm) 1) Test with a single AD-box on speedmode 4 2) Test with 1 AD-box (speedmode 4) plus AIB (speedmode 8) 3) Test with two AD-boxes (speedmode 0 and speedmode 1) Test with the CMS/DRL and...
- Thu Mar 23, 2006 3:54 pm
- Forum: EEG data analysis
- Topic: neuroguide and biosemi
- Replies: 1
- Views: 7974
Neuroguide list BioSemi BDF as a supported file format on http://www.appliedneuroscience.com/EEG%20Formats.jpg . However, I have not yet heard of customers actually using this combination.
Best regards, Coen (BioSemi)
Best regards, Coen (BioSemi)
- Mon Mar 13, 2006 4:08 pm
- Forum: BioSemi all other topics
- Topic: BDF structure
- Replies: 2
- Views: 9742
ActiView writes BDF file with 1 second record length. So, the number of samples in a record is equal to the sampling rate. The number of samples per record is always listed in the file header, see http://www.biosemi.com/faq/file_format.htm
Best regards, Coen (BioSemi)
Best regards, Coen (BioSemi)
- Tue Mar 07, 2006 6:41 pm
- Forum: EEG data analysis
- Topic: merging BDFs?
- Replies: 10
- Views: 35464
In principle, merging of two files only involves deleting the header of the second file, adding the data section of the second file to the first file, and adjusting the length field in the header of the first file to the new value (total length of the two files). In LabVIEW, the code will be quite s...
- Wed Feb 08, 2006 7:36 pm
- Forum: EEG data analysis
- Topic: Trigger display
- Replies: 4
- Views: 13985
Unconnected trigger lines are high due to the internal pull-up resistors in the USB receiver. The "baseline correction" described above is a good solution. An alternative is to connect all unused trigger lines to ground (pin 37 on the trigger port). The 16 trigger bits should not be regarded as an a...