Device window
© Copyright by Neurobit Systems 2010-2021
http://www.neurobitsystems.com
Neurobit Driver enables applications to communicate with biofeedback and
physiological data acquisition equipment by Neurobit Systems. In the device
window created by the driver you can set configuration of a given device.
For some devices, such as Neurobit Optima, it is also possible to test
electrode-skin impedances & input circuit continuity.
The driver is running under Microsoft Windows 10/8/7/Vista/XP systems.
Contents:
Neurobit Optima[+] Bluetooth 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 Neurobit Optima Quick Start Guide.
Neurobit Optima device should be set in wireless communication range (usually
a few meters). Before the 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 Optima[+] USB devices:
A cable with full size USB 2.0 male A connector on one end and micro B male
connector on the other end (the same as for typical cell phone chargers) is
required. Install driver software for USB chip by FTDI, as described in the
device quick start guide. Connect the computer to the device and turn it on.
The computer should detect the device and install the driver necessary for
its USB module.
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 nearby.
The device window is divided into several tabs, which can be selected in the upper bar or with the Next button in lower right-hand corner of the window. The tabs contain options which depend on a selected device. These are the General tab with general device options and several tabs with settings for individual measurement channels. Additional tabs may also appear for some devices, e.g. Test tab.
As an example, settings for Neurobit Optima+ 4 device are described below. Please consult instruction manual of your device model to learn about available settings.
Device model - a specific device type within the Neurobit Optima subfamily (selected in BioExplorer's device manager). ONLY for BioExplorer v. 1.*. In other cases, the complete device type is selected in an application window (outside the device settings window described here).
Link type - the type of link used for communication with the device.
If you have only one turned on Neurobit device paired with your computer or connected to it via USB, you can use the abovementioned generalized identifier in this field. Otherwise you need to identify each device unambiguously with its transceiver identifier. To check the identifiers follow instructions given in remarks of the Neurobit Loader help.
Mains power frequency [Hz] - sets the 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 the user's geographic location (country) set in the system ("Control Panel"/"Regional and Language Options"/Location), when the Neurobit Driver starts for the first time, or when a user has changed the geographic location in the system since the 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 sometimes be necessary, for example:
Silent mode - turns off sound signaling of events (artifacts etc.) in the
device during measurements.
Visual signaling is not influenced.
(The option is insignificant on the devices without sound transducer.)
Device services button - opens the application that provides device service functions, especially firmware updates.
Neurobit Optima devices have versatile measurement channels, which functions can be defined by a user. It should be taken into consideration, that the appearance and available settings of some parameters (e.g. Measurement range) may depend on other parameters (e.g. Channel function). When you change superior parameter, its dependent parameters are set to defaults.
Channel enable - checkbox enabling the measurement channel.
Channel label
A short label for the channel (e.g. "EEG Cz"), which may be used by an application.
It is filled in automatically when the channel profile is changed manually on a channel tab (to an option other than "User defined"), and/or when the EEG cap connection is modified with settings on the cap tab (the cap enable, a set of connections, or site connected to a channel).
A label set this way can be changed manually afterwards. (The vhannel label is limited to 16 characters. It can be empty.)
Sensor info
You can enter here your short description of
the transducer used (e.g. "AgAgCl electrode"), which may be used by an application.
(This description is optional. It is limited to 80 characters.)
Channel profile
The profile enables the default parameters for some basic types of
physiological signals to be set in one step (the fields of those
parameters are then locked).
In order to freely set all parameters by yourself select the "User defined" option. It unlocks the rest of the parameters without changing them. (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, then select the "User defined" profile and make the required minor changes.)
Channel function
It enables the measurement of voltage (default) or another physical quantity to be selected.
Frequency characteristic
For voltage signals, this option enables the signal delay to be minimized
or frequency bandwidth to be maximized. E.g. for
the "Linear phase sharp" option the frequency bandwidth (in Hz) is 40% of the sample rate,
and the signal delay of analog-to-digital conversion is 19 samples.
For the "Linear phase mild" characteristic, the bandwidth is 30% of the sample rate,
with an 11 sample delay.
Measurement range - selects the upper limit of signal values that
can be measured.
A higher range protects against clipping of high amplitude signals,
while a lower range makes measurement more sensitive, thus reducing the quantization noise
of analog-to-digital conversion.
(Note when the Channel function is set to measure conductance: the unit 1uS (micro Siemens) equals 1micromhO used in electrophysiology.)
Range minimum - the lower limit of measured signals (a read-only value which depends on the Measurement range setting).
Sample rate - selects number of output signal samples per second.
A higher sample rate enables faster signals to be measured, whereas a lower sample rate
reduces high frequency noise, as well as the computational load of the processor and the size
of the recorded signal files.
Lower limit frequency - selects the lower limit of frequency band, in which the signal is measured. Lower values enable slower signals to be measured, whereas higher values reduce low frequency noise and shorten transient states after sensor (dis)connection.
Value 0 (DC coupling), if available, should be used with care, as electrode DC offset is not removed for such a setting and could saturate the amplifier.
Power interference filter - turns on or off the device's mains
power interference filter.
(The filter notch frequency is set by the Mains power frequency
option on the General tab.)
Sum disconnected
This option disconnects the sum voltage in the channel
from the common voltage feedback amplifier (generating virtual ground potential).
It has to be cleared for channels galvanically connected to the body
(measuring EEG, EMG, GSR etc. signals on the skin surface). It is recommended to set
this option for sensors without galvanic contact to the body (e.g. temperature probe).
Common reference
This option defines the connection of the negative ("-") input of the given channel to
a common reference electrode. (It applies only to channels with the function set to "Voltage".)
For Neurobit Optima[+] BT/USB devices:
There is an option of "Internal connection" to the common reference. Negative inputs of channels with such a selection are electronically linked together inside the device, and a common reference electrode should be connected directly to any of those inputs. No external jumper is necessary.
(If a so called "linked ears" circuit is used, the electrodes on both ears should be connected directly to any negative inputs linked internally.)
If, in some application, two independent common references are necessary (e.g. one for channels A and B measuring EEG and another for EOG measurement on channels C and D), the second one requires "External connection" tp be set for the corresponding channels. And the negative inputs of the corresponding channels should be connected together and to a reference electrode with an external jumper.
For older Neurobit Optima models:
Up to two external common references can be selected. Negative inputs of the corresponding channels have to be linked together and to a reference electrode(s) with an external jumper(s).
For all devices:
For bipolar derivations (channels measuring voltage differences between independent pairs of electrodes) the Common reference field should be set to "No connection". The same setting applies to voltage measurements without a galvanic connection to the body (e.g. with a piezoelectric respiration sensor).
IMPORTANT: Even if the negative inputs are not linked internally in the device, proper setting of the Common reference field is necessary for correct electrode-skin impedance readings on the Test tab.
EEG cap connection - shows the EEG cap site connected to the channel for devices equipped with the cap interface. Cap connections are controlled with settings on the EEG Cap tab described below.
Parameters for channels B-E are set similarly as for channel A.
For devices equipped with EEG cap interface this tab enables the connections of cap electrodes to individual measurement channels to be controlled.
Cap enable - enables the cap interface.
Immediately after checking this option all of the measurement channels are automatically:
If necessary, individual channel settings can be modified manually afterwards.
Unchecking this option does not change the settings on the channel tabs, except for EEG cap connection, which is set to "None" (and a corresponding change in the channel label).
Set1-5 - current set of cap sites linked to individual channels. The selected sites are shown in the Connections section of the tab.
5 available sets for 4 channel device enable all 19 sites of the International 10-20 EEG System (and one additional site) to be covered. It facilitates full QEEG evaluations (divided into 5 steps), among other things.
Connections - this section enables the connections of individual channels to the cap sites for the current set to be selected. (The lists of sites available for consecutive channels were chosen to maximize the number of practically useful combinations of sites for the available number of device channels.)
Site selections are disabled for channels, which are disabled or set to a function other than "Voltage".
Note: For channels connected to the cap, the general purpose positive inputs (A+, B+ and so on) should not be used. However it is possible to connect only some channels to the cap, and use others independently from the cap.
This tab enables input circuit connections and electrode-skin impedances for enabled channels to be tested before an actual signal recordings. Although optional, execution of the test is recommended.
Note: The test tab is not shown when the device window is opened during a regular measurement session.
The state indicators shown on this tab can have up to four states:
Window contents:
Link - the state of the data link between measurement device and the computer.
It is red if the link is lost. This condition usually appears when the wireless device moves
out of the communication range.
If the device is quickly brought closer
to the computer, the link will be restored and the session will continue. (If the
communication disruption lasts for longer than about 60 seconds, the session will end.)
Battery - the state of the batteries in the wireless device.
If the indicator
turns red (batteries flat), the device will turn off shortly. To avoid this
situation it is recommended to replace the batteries, when the indicator turns yellow
(batteries become weak).
Pause - not used for Neurobit Optima(+).
Common voltage - indicator of common voltage interference.
The so-called common voltage on the 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 the dynamic range of the amplifier. To avoid uncontrolled conditions of poor
signal quality, Neurobit Optima(+) supervises the common voltage and indicates when it is too high
(the indicator turns red). In most cases the cause of this condition is a lack of
electrical contact between the Virtual Ground (VG) line and the examined subject's body.
Channel A - the state of the signal in channel A.
In moments, when the signal goes
beyond the measurement range, this indicator turns red. It is usually caused by bad
electrical contact of a sensor or high amplitude interference. This condition could also
occur with a correct connection and input signal if too small measurement range was set
for the channel.
The yellow indicator means the lack of a signal. This condition is detected when the measured signal is many times lower than the measurement range for a long time (consult the equipment manual for specific limits). Depending on the 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 a short circuit of the electrodes of both channel inputs (maybe due to an excessive amount of conductive gel). This condition may also occur with correct connections, as a result of too large a measurement range set for the channel.
Channel B-E - states of signals in channels B-E, similar as for the channel A.
Impedance indicators
For channels with voltage measurement setting there are
two sets of indicators of electrode-skin impedance on the + and - inputs of the differential channel.
For channels with a non-voltage measurement setting, there is one set of indicators of connection
resistance between + and - inputs of the channel. The indicators for disabled channels are inactive.
Each set of indicators includes a bar gauge and digital value of impedance (resistance).
The bar gauges for channels with a voltage measurement setting change their colors depending on the impedance level:
NOTES:
Test button - initiates a test.
When physical measurement starts, the indicators become active. During the test most of the
configuration options are locked. The test can be ended with the Stop button (which
replaces the Test button while a test is running).
IMPORTANT: For multi-channel measurements of voltage signals (for example EEG), suitable settings of the Common reference fields on individual channel tabs are necessary for correct electrode-skin impedance readings.
This tab is shown only when the device window is opened during regular measurement session. It enables the session state to be checked, if not presented directly in an application window. The tab includes more detailed information than seen on the device, with separate indicators for individual measurement channels:
The meaning and states of these indicators are described above in Test tab section.
Information about the driver's manufacturer, its license and help are available here.
For BioExplorer v. 1.*, only Neurobit Optima subfamily (2 or 4-channel) is chosen in the device manager of the application, whereas a specific device model is selected on the General tab in the device settings window.
For interoperation with the BioExplorer application (v. 1.*), which does not store Neurobit device settings along with a design, there are two additional buttons at the bottom of the window to facilitate device configuration:
NOTES:
For Neurobit Lite device: please remember that the computer-based session is initiated from the computer side, and not with the Start! command from the device's menu. (For stand-alone trainings initiated with the Start! command in the device, no data is transmitted to the computer.)