Multichannel Systems USB-MEA32-STIM4 Manual - Manual (Page 15)

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4 USB-MEA32-STIM4-System
4.1 The USB-MEA32-STIM4-System Components
4.1.1 Filter Amplifier
The filter amplifier combines a band pass filter and the signal amplification in one instrument.
The bandwidth of 0.5 Hz to 3000 Hz is suitable for a broad range of applications, such as spikes
and field potential recordings. The digital filter of the MC_Rack program can be used to adjust
the pass band and filter the raw data. Please see the MC_Rack help or manual for more
information. For most LTP experiments, it is recommended to use a digital 10 Hz high pass filter
to avoid low frequency noise.
Please note that the gain factor of the filter amplifier (1000) is a fixed hardware property that
cannot be changed by software controls. Please also note that the ratio of the output signal to
the input signal, that is, the gain, is not a fixed parameter for the complete bandwidth. The gain
that was specified for the amplifier, for example, 1000 is not fully reached at the borders of the
amplifier's pass band. The general rule is, that at the lower and upper limit of the frequency band,
the gain is approximately 70 % of the full gain. Therefore, you should use a bandwidth that is at
a safe distance of the signals of interest. Outside the pass band, the gain decreases with the
frequency and finally approaches zero.
For more information on gain and filters in general, please refer to standard literature or contact
your local retailer.
Raw data from up to 32 electrodes of a microelectrode array MEA is amplified by 32 channels
of filter amplifiers that are built very small and compact using SMD (Surface Mounted Devices)
technology. The small-sized MEA amplifier combines the interface to the pMEA probe with the
signal filtering and the amplification of the signal. The compact design reduces line pick up and
keeps the noise level down. The MEA sensor is placed directly into the small-sized USB-MEA32-
STIM4 amplifier. When the amplifier is closed, the contact pins in the lid of the amplifier are
pressed onto the MEA contact pads. The very close location of the amplifier to the MEA sensor
is very favorable concerning a high signal-to-noise ratio.
The amplifier is intended to be used with a binocular or an inverted microscope.
The USB-MEA32-STIM4 amplifier is compatible with most standard microscopes.
If necessary, you can use a Faraday cage or appropriate materials, for example, aluminum foil
for shielding the amplifier. The shielding should be connected to the amplifier's ground.