© Copyright by Neurobit Systems 2010-2012
Neurobit Recorder (record.exe) is a simple, yet creating many possibilities
enables to record physiological signals collected wirelessly with equipment by Neurobit
Systems. Data can be stored on a computer disk in European Data Format (EDF) or text files.
They can be imported by many signal analysis or spreadsheet applications, such as
EEGLAB for Matlab,
Polyman or Excel
(including some freeware). For some devices, such as Neurobit Optima, the Neurobit
Recorder can also test electrode-skin impedances & input circuit continuity.
The application is running under Microsoft Windows 7/Vista/XP/2000 systems.
Neurobit Optima devices:
Bluetooth communication port (built-in into a computer or as a USB adapter) compatible with the protocol version 1.1 or newer is required. To install Bluetooth adapter follow an instruction delivered in its package.
Neurobit Optima device should be set in wireless communication range (usually less than 10m). Before use a Bluetooth device should be paired with your computer. Pairing code for Neurobit Optima is 0000. You can learn more about Bluetooth pairing in Windows help.
Neurobit Lite devices:
Infrared (IR) communication port (built-in into a computer or in form of a USB adapter) compatible with IrDA standard v. 1.0 or newer is required. To install IrDA adapter follow an instruction delivered in its package.
The Neurobit Lite device should be set with IR port oriented towards IR port of your computer, no more than 0.5m from it, without physical obstructions between both entities, preferably on the same axis. There should be no other active IrDA devices (like cell phones) nearby.
HINT: If you used older BioEra software requiring IrComm2k driver (i.e. not using Neurobit Driver 3.0 or later version), set the driver in "Standard" mode or uninstall it completely.
(In order to uninstall the application the uninstall.bat program from the application folder can be used.)
The main application window is divided into several tabs, which can be selected in the bar below main menu or with Next button in lower right corner of the window. Apart from the common Session tab there are tabs of options depending on a selected device. These are a General tab with general device options and several tabs with settings for individual measurement channels. There may also appear additional tabs for some devices, e.g. Test tab. The Record tab enables to run measurements with configuration set on previous tabs.
As an example, settings for Neurobit Optima 2 device are described below. (Use of Neurobit Driver 3.0 is also assumed.) Please consult instruction manual of your device model and version to learn about available settings.
You can enter here a short session description (up to 80 characters for EDF format), which will be saved in recording file. (This setting is optional.)
You can enter here a short information about examined person. The information (up to 80 characters for EDF format) will be saved in recording file. (This setting is optional.)
Recording duration can be given here in hh:mm:ss format (hours and minutes can be omitted). After the specified period of time the recording will be automatically stopped. (If necessary, it is still possible to shorten a recording session, stopping it manually; it is also possible to change time limit during the session.)
If this field is empty (or set to 0), the recording time is not automatically limited (measurement should be stopped manually).
One of measurement devices supported by the application is selected here.
Output format - selects format of the recording file.
EDF is a default. It is one of often used de facto standards for physiological signals.
The alternative text format (Tab Separated Values) needs many times more space, than binary EDF; also generated text files are not compatible with typical physiological signal analysis software. Thus this format should be used only when brief recording of data for spreadsheet or similar general purpose applications is required.)
Many other formats for bio-signal files are in use, e.g. BDF, GDF, EEG, CNT, AVG. If you need a file in another format, you can use one of free EDF converters available in the web.
Output file - name of the recording file (including its folder
path, if current folder is not used).
In order to browse folders on your computer, you can click Browse folders button below the file field. The path and file name selected in the browse window will be copied to "Output file" field.
Link type - type of link used for communication with the device.
Device address - Bluetooth address of Neurobit device (or name of
its communication module).
If you have only one turned on Neurobit Optima device in the wireless communication range, you can usually leave the default value in this field. (Otherwise it is recommended to set here a specific address of a given device. Addresses of Bluetooth devices seen by your computer can be listed in system "Control Panel"/"Bluetooth Devices".)
Power mains frequency [Hz] - sets mains frequency used in your
country, required for power interference filtering in the device.
For example, most European countries uses 50 Hz mains, while 60 Hz is used in North America. In most cases you can leave the default setting.
NOTES: The power frequency is set automatically, based on user's geographic location (country) set in the system ("Control Panel"/"Regional and Language Options"/Location), when the Neurobit Driver starts the first time, or when a user has changed geographic location in the system since previous start of the driver. The setting is then stored in the system registry. It is common for all applications using Neurobit Driver. Unlike other device settings, the power frequency is not read from design or configuration files.
Nevertheless, manual frequency selection may be sometimes necessary, for example:
Silent mode - turns off sound signalization of events (artifacts etc.) in the
device during measurements.
Visual signalization is not influenced. (The option is insignificant in devices without sound transducer.)
Device services button - opens the application of device service functions, for example firmware upgrade.
Neurobit Optima devices have versatile measurement channels, which functions can be defined by a user. It should be taken into consideration, that appearance and available settings of some parameters (e.g. "Measurement range") may depend on other parameters (e.g. "Channel function"). When you change such superior parameter, all dependent parameters are set to defaults.
Channel enable - enables or disables the measurement channel.
You can enter here your short label for the channel (e.g. "EEG FpzCz"), which will be stored in the recording file. (The label is optional. For EDF files it is limited to 16 characters.)
You can enter here your short description of used transducer (e.g. "AgAgCl electrode"), which will be stored in the recording file. (This description is optional. For EDF files it is limited to 80 characters.)
The profile enables to set in one step the default parameters for some basic types of physiological signals (fields of those parameters are locked then).
In order to freely set all parameters by yourself select "User defined" option. It unlocks rest of the parameters without their change. (Thus if you would like to use default settings of most parameters for a specific profile (e.g. EEG) and set only one or two parameters on your own, you can first select that specific profile, next select "User defined" profile and do required minor changes.)
It enables to select measurement of voltage (default) or other physical quantity.
For voltage signals this option enables to minimize signal delay or maximize frequency bandwidth. E.g. for "Linear phase sharp" option the frequency bandwidth (in Hz) is 40% of sample rate, and signal delay of analog-to-digital conversion is 19 samples. For "Linear phase mild" characteristic the bandwidth is 30% of sample rate, with 11 samples delay.
This parameter is replaced with Thermistor characteristic for channel function set to Temperature.
Measurement range - selects upper limit of signal values, which
can by measured.
Higher range protects against clipping of high amplitude signals, while lower range makes measurement more sensitive, thus reduces quantization noise of analog-to-digital conversion.
(Note for "Channel function" set to conductance measurement: the unit 1uS (micro Siemens) equals 1micromhO used in electrophysiology.)
Range minimum - lower limit of measured signals (read only value depending on "Measurement range" setting).
Sample rate - selects number of output signal samples per second.
Higher sample rate enables to measure faster signals, whereas lower sample rate reduces high frequency noise and size of recorded files.
Power interference filter - turns on or off device's filter of power
(Filter notch frequency is set by "Power mains frequency" option on General tab.)
The option disconnecting sum voltage in channel from common voltage feedback amplifier (generating virtual ground potential). This option have to be cleared for channels galvanically connected with body (measuring EEG, EMG, GSR etc. signals on the skin surface). It is recommended to set the option for channels connected to transducers with asymmetric (two-wire) voltage output.
This option informs of external connection of "-" input of a given channel to a common reference electrode. Its suitable selection is required for correct results of electrode-skin impedance tests for such inputs. Up to two independent common references are supported.
(This setting does not cause any internal connections of inputs in the device. It also has no influence on regular measurements - apart from tests of electrode-skin impedances. It does not apply to channel functions different than "Voltage".)
Parameters for channel B are set similarly as for channel B.
This tab enables to test input circuit connections and electrode-skin impedances for enabled channels before actual signal recordings. Although optional, execution of the test is recommended.
State indicators (Link, Battery, Pause,
Common voltage, Channel A, Channel B)
See similar indicators on Record tab.
For channels with voltage measurement setting there are two sets of indicators of electrode-skin impedances on inputs + and - of the differential channel. For channels with non-voltage measurement setting there is one set of indicators of connection resistance between + and - inputs of the channel. Indicators for disabled channels are inactive. Each set of indicators includes bar gauge and digital value of impedance (resistance).
Bar gauges for channels with voltage measurement setting change their colors depending on impedance level. For recommended low electrode-skin impedance they are green, when impedance goes higher to acceptable level, they become yellow. For unacceptably high impedances the gauges are red.
HINT: When signal state indicator for a given channel (or "Common voltage" indicator) is red (signal is invalid), impedance indicators are not updated.
Test button - initiates test.
When physical measurement starts, the indicators become active. During the test most of the configuration and menu options are locked. The test can be ended with Stop button, which appears instead of Test button.
HINT: For multi-channel measurements of voltage signals (for example EEG), suitable settings of Common reference fields on individual channel tabs are necessary for correct electrode-skin impedance readings. For reference derivations (with common reference electrode) connection of - inputs to that electrode should be selected ("Reference 1" option if single reference electrode is used). For bipolar derivations the Common reference fields should be set to "No connection" (it is the default).
This tab is used to record signals in accordance with configuration set on other tabs.
State indicators shown on this tab can have up to four states:
Link - state of wireless link between measurement device and computer.
It is red, if the link is lost. This condition usually appears when the device goes out of wireless communication range (typically 10 meters for Neurobit Optima). If the device will be quickly brought closer to a computer, link will be restored and recording will continue. (If lack of communication is longer than about 60 seconds, recording will be ended.)
Battery - state of battery(ies) in measurement device.
If the indicator gets red (batteries flat), the device will turn off in a while. To avoid this situation it is recommended to replace batteries, when the indicator gets yellow (batteries become weak).
Pause - not used for Neurobit Optima.
Common voltage - indicator of common voltage interferences.
So called common voltage on inputs, which would strongly interfere with measurement of small electrophysiological signals, is almost totally removed by differential amplifiers. However, it is true only as far as the common voltage is within dynamic range of the amplifier. To avoid uncontrolled conditions of pure signal quality, Neurobit Optima supervises common voltage and indicates when it is too high (the indicator becomes red). In most cases the cause of that condition is lack of electrical contact between Virtual Ground (VG) line and examined subject's body.
Channel A - state of signal in channel A.
At moments, when the signal goes beyond measurement range, this indicator gets red. It is usually caused by bad electrical contact of sensor or high amplitude interferences. This condition could also appear with correct connection and signal, if too small measurement range was set for the channel.
The yellow indicator means lack of signal. This condition is detected when measured signal is many times lower than measurement range for long time (consult the equipment manual for specific limits). Depending on type of signal it may be normal from time to time. If the condition occurs frequently or all the time, it may be caused by short circuit of electrodes of both channel inputs (maybe with excessive amount of conductive gel). This condition may also occur with correct connections, as a result of too large measurement range set for the channel.
Channel B - state of signal in channel B, similarly as for Channel A.
Record button - initiates recording.
If the output file already exists, question about its rewriting appears. They may also be shown other messages, for example if link between the device and computer cannot be established.
When physical measurement starts, recording progress info appears above the button and state indicators become active. During recording most of the configuration and menu options are locked.
If "Time limit" was set on the Session tab, recording will be stopped automatically, when that period expires. Session can be also stopped manually at any time with Stop button appearing instead of Record button.
The only physical limit of recording time is free space on disk, where output file
Example: For EDF output format each signal sample occupies 2 Bytes. If there are two enabled channels sampled at 250 sps, it yields 2 * 2 * 250 = 1000 Bytes per second, i.e. 3.6 MBytes per hour. For higher sample rate or more active channels data size will proportionally increase.
Load device settings (F3) - loads device configuration saved earlier in file.
Settings on the Session tab remain unchanged, apart from "Device name" field.
Save device settings (F2) - saves device configuration in file.
Settings on the Session tab are not stored, apart from "Device name" field.
HINT: Apart from manual saving with this option, the application automatically stores current configuration at the beginning of measurement and before exit. This configuration is automatically loaded, when the application is started next time.
Device services - it opens an application of device service functions,
for example firmware upgrade.
(The service window can be also opened with "Device services" button on General tab.)
Exit - closes the application.
It gives access to the application documentation (F1), license and information about the manufacturer.
For Neurobit Lite devices: please remember that computer-based session is initiated from computer side, and not with Start! command from the device's menu. (For stand-alone trainings initiated with Start! in the device, no data is transmitted to computer.)
Episodes of artifacts are not cut out from recorded data to avoid loss of time information.
Additional information in the equipment Instruction Manual may apply to the product use with a computer.