Search found 1124 matches

by Coen
Fri Aug 01, 2008 12:33 pm
Forum: EEG data analysis
Topic: measuring eeg signals
Replies: 1
Views: 6402

We from the BioSemi company recommend to use the BioSemi ActiveTwo system for your project.

Best regards, Coen (BioSemi)
by Coen
Tue Jul 29, 2008 11:52 am
Forum: BioSemi all other topics
Topic: BDF Byte Reading c#
Replies: 8
Views: 15478

In your example, speedmode (bit 0 ..bit3) would be 0011 which would mean speedmode = 12. Speedmode 12 is not used on any ActiveTwo, so you must be doing something wrong.

Best regards, Coen (BioSemi)
by Coen
Fri Jul 25, 2008 11:56 am
Forum: BioSemi Software (ActiView executable)
Topic: TCP dropped packets
Replies: 8
Views: 21500

TCP/IP is a handshaked protocol, packages cannot be lost without an error warning. ActiView can be checked with the LabVIEW client available from http://www.biosemi.com/download/ActiveTwoClient_8.zip . Testing shows that no packages are lost. There must be a bug in your Matlab client. Best regards, ...
by Coen
Mon Jul 21, 2008 4:36 pm
Forum: BioSemi Hardware
Topic: Differential Amplification
Replies: 6
Views: 23408

The selected sample rate does not influence the DRL circuit. As explained above, the DRL circuit offers less CM rejection at higher frequencies. Because a higher sample rate means a higher bandwidth, you may see higher harmonics of 50 Hz in recordings made with a higher sample rate. However, if all ...
by Coen
Mon Jul 21, 2008 12:25 pm
Forum: BioSemi all other topics
Topic: recording of high frequency oscillatory activity
Replies: 3
Views: 9910

The BioSemi ActiveTwo system with active electrodes has a flat frequency response (DC till 1/5th of the sample rate) and a high input impedance (1 TeraOhm parallel with 11 picoFahrad). This ensures that no enhancement or decrease of any frequencies in the passband is experienced, even with high elec...
by Coen
Mon Jul 21, 2008 11:50 am
Forum: BioSemi Hardware
Topic: Vista 64 bit driver
Replies: 1
Views: 4447

A 64-bit Vista driver is under development.

Best regards, Coen (BioSemi)
by Coen
Mon Jul 21, 2008 11:47 am
Forum: BioSemi all other topics
Topic: recording of high frequency oscillatory activity
Replies: 3
Views: 9910

The statement about enhancement of the high-frequency oscillatory components is nonsense. I do not think that it is justified to post such accusations without any argument or proof. I feel that the "lecturer who is considered to be an eeg expert" should reveal himself or herself. In addition, you sh...
by Coen
Thu Jul 17, 2008 11:06 am
Forum: BioSemi Software (LabVIEW programming)
Topic: Biosemi software
Replies: 3
Views: 20960

Reading constant sized blocks of data from the ringbuffer is no problem. A simple change to the ActView code achieves this (best to test in ActiView Light). However, this is something else than keeping the backlog constant. Actually, reading constant sized data blocks from the ringbuffer will increa...
by Coen
Wed Jul 16, 2008 12:50 pm
Forum: BioSemi Software (LabVIEW programming)
Topic: Biosemi software
Replies: 3
Views: 20960

ActiView maintains a MINIMAL backlog, which is the best you can do within the constraints of the Windows operating system. Please explain why you would want to maintain a CONSTANT backlog.

Best regards, Coen (BioSemi)
by Coen
Tue Jul 01, 2008 11:51 am
Forum: BioSemi Software (ActiView executable)
Topic: error 5000 and error 5001
Replies: 1
Views: 8416

Because we replaced your motherboard due to the earlier discussed water damage, your AD-box is now a version Mk2 (also see http://www.biosemi.nl/forum/viewtopic.php?t=270 ). However, your (old) USB receiver only recognizes Mk1 boxes. Please send your USB receiver for reprogramming to the latest firm...
by Coen
Fri Jun 27, 2008 5:00 pm
Forum: EEG data analysis
Topic: Newbie Question: How to view data in BDF file header
Replies: 3
Views: 8747

The most simple method is to use the file cropper (http://www.biosemi.com/download/Cropper.zip) to extract a BDF file with a length of 1 second, and then to open the this small BDF file in notepad (do not try to open a large BDF file in notepad).

Best regards, Coen (BioSemi)
by Coen
Fri Jun 20, 2008 6:46 pm
Forum: BioSemi Software (ActiView executable)
Topic: TCP/IP Server/Client
Replies: 1
Views: 5452

A new version of the client compiled in LabVIEW 8.2 is now available for download from http://www.biosemi.com/download/ActiveTwoClient_8.zip (exe and vi).

Best regards, Coen (BioSemi)
by Coen
Mon Jun 16, 2008 3:53 pm
Forum: BioSemi Software (LabVIEW programming)
Topic: TCP connection
Replies: 5
Views: 24186

The TCP tab does not gray out, just the channel selectors on the TCP page. You can select the page during running acquisition, and all relevant information is visible. You can't change the channels sent by TCP during running acquisition (because this would change the packets size), you have to selec...
by Coen
Fri Jun 13, 2008 3:42 pm
Forum: BioSemi Software (LabVIEW programming)
Topic: TCP connection
Replies: 5
Views: 24186

You can set: - Sample rate (with speedmode selector in hardware and decimation in software) - "Sent local port", best to leave on the default setting of 778, select on TCP/IP tabpage - "TCP subset", this select the channels sent by TCP/IP, select on TCP/IP tabpage ActiView then determines the packet...
by Coen
Wed Jun 11, 2008 6:08 pm
Forum: BioSemi Software (LabVIEW programming)
Topic: TCP connection
Replies: 5
Views: 24186

The packet size for the TCP/IP transfer is constant. The size is controlled by the settings in ActiView, and depends on the number of transfered channels, and the sample rate. The packet size is displayed on the TCP/IP tabpage after acquisition is started. The settings influencing the packet size ca...
by Coen
Tue Jun 03, 2008 4:42 pm
Forum: BioSemi Hardware
Topic: power up problem
Replies: 5
Views: 9367

Please send only the AD-box, in your case it is not necessary to send the batteries.

Best regards, Coen (BioSemi)
by Coen
Thu May 29, 2008 2:11 pm
Forum: BioSemi Software (ActiView executable)
Topic: 128 channel configuration file
Replies: 1
Views: 6168

The normal procedure is to select the proper settings for the controls in ActiView for 128 channel use, and then save this configuration in a new CFG (via the "About ActiView" tabpage).

In case of problems, please email me your 64-chan CFG, and I will modify it to 128 channels

Best regards, Coen
by Coen
Fri May 23, 2008 4:00 pm
Forum: BioSemi Hardware
Topic: CMS and DRL?
Replies: 1
Views: 5475

The only difference between the P-32-1020-64ACMS and the P32-1020-32ACMS sets are the labels on the electrodes, the sets are technically identical. I expect that your "flat line on all channels" issue occurred together with a flashing blue light. Signals can only be measured when the Common Mode is ...
by Coen
Mon May 19, 2008 12:04 pm
Forum: BioSemi Hardware
Topic: power up problem
Replies: 5
Views: 9367

The AD-boxes are normally very reliable, there are no known issues. The few problems we have seen in the past years were nearly always related to connectors (user abuse). There are no obvious points for you to check or repair. Please sent the box to us in Amsterdam.

Best regards, Coen (BioSemi)
by Coen
Fri May 16, 2008 3:04 pm
Forum: BioSemi Hardware
Topic: USB Box
Replies: 5
Views: 8542

Thanks, we can then be pretty sure that the driver is correctly installed. Just to be sure, I recommend to test a last time with a complete working front-end (your older optical fiber AND AD-box, not necessary to connect any electrodes for a basic test). If the error remains, than I see no other opt...
by Coen
Fri May 16, 2008 1:17 pm
Forum: BioSemi Hardware
Topic: USB Box
Replies: 5
Views: 8542

Do you hear a "plong" sound when you plug in, or unplug the USB cable at the receiver ? Is "BioSemi USB" listed in the Windows Device manager (should appear when the USB cable is plugged in the receiver, should disappear when the USB cable is unplugged) ? The two tests above indicate whether the dri...
by Coen
Fri May 16, 2008 12:46 pm
Forum: BioSemi Hardware
Topic: USB Box
Replies: 5
Views: 8542

Given you have another (working) ActiveTwo system, I would suggest to swap the USB receiver. If the USB receiver from the other system works, then sent the non-working USB receiver for repair to your local BioSemi representative. If the USB receiver form the other system doesn't work either, then sw...
by Coen
Thu May 15, 2008 12:47 am
Forum: BioSemi Hardware
Topic: power up problem
Replies: 5
Views: 9367

The box switches off because the safety circuit detects a short between the case shield and one of the internal power lines (a few tens of uA is enough leakage current to trigger the safety circuit) Please sent the box to us in Amsterdam for repair. After inspection of the box, we can probably expla...
by Coen
Wed May 14, 2008 1:08 pm
Forum: BioSemi all other topics
Topic: Other platforms
Replies: 23
Views: 93837

The reason for not investing in the development of drivers for operating systems other than Windows is that we do not feel it will be commercially worthwhile.

We do not plan to make the source code of the Windows driver available because of competitive reasons.

Best regards, Coen (BioSemi)
by Coen
Mon May 12, 2008 11:46 am
Forum: BioSemi all other topics
Topic: Other platforms
Replies: 23
Views: 93837

The critical part is the USB driver. The driver is only available for Windows XP and Vista.

Best regards, Coen (BioSemi)
by Coen
Tue May 06, 2008 4:01 pm
Forum: BioSemi Software (LabVIEW programming)
Topic: Constant data blocks?
Replies: 1
Views: 18968

It is the same in Light and the Full version of ActiView. The principle of the variable data blocks is most easy understand by studying the Light version first. ActiView varies the amount of data read form the ringbuffer and plotted to screen according to the backlog (amount of new unprocessed data ...
by Coen
Tue May 06, 2008 12:24 pm
Forum: BioSemi Software (ActiView executable)
Topic: marialaura
Replies: 1
Views: 5732

The current TCP client is only made available as Virtual Instrument (not as executable) running under LabVIEW 8.2. The client VI is meant as a basis for further LabVIEW developments. You can run the old client executable with RTE 7.1 (ftp://ftp.ni.com/support/labview/windows/runtime/7.1/LVRunTimeEng...
by Coen
Thu Apr 24, 2008 5:39 pm
Forum: EEG data analysis
Topic: bipolar EEG
Replies: 1
Views: 6327

Bipolar leads can be constructed in off-line review software.

Best regards, Coen (BioSemi)
by Coen
Thu Apr 24, 2008 5:37 pm
Forum: BioSemi all other topics
Topic: maria laura
Replies: 1
Views: 6838

It is certainly possible to use the BioSemi system during arm and leg movements. Just be careful that the cap does not shift on the head (this will lead to movement artifacts). Any of the electrodes, or combination of the electrodes can be used as a reference, see http://www.biosemi.com/faq/cms&drl....
by Coen
Wed Apr 23, 2008 5:19 pm
Forum: BioSemi Hardware
Topic: Shielding in EEG
Replies: 8
Views: 21759

We have successfully performed interference-free EEG recordings with the BioSemi ActiveTwo system near MRI rooms (a distance of 10-20 meters from the shielded room). However, given the large variation in technical details of MRI in setups, I can only recommend to do some actual tests with an ActiveT...