Specifications

Extracellular Recording from MEAs

Please 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, 1200, 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

2/2 , that 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.

The low-pass filter properties of the MC_Card will affect the bandwidth of the complete system

only slightly.

For information on the gain and filters of the MEA amplifiers, please see the appropriate MEA

Amplifier Manual. For more information on gain and filters in general, please refer to standard

literature or contact your local retailer.

3.4.3 Data Acquisition

Recording from up to 128 channels is easy with the MC_Card hardware and the MC_Rack

software.

MC_Card hardware

Important: You need to have installed the latest MC_Card driver to operate the MC_Card, which is

usually preinstalled on the data acquisition computer. The installation may be invalid if the

MC_Card does not respond. Please contact Multi Channel Systems if you need the MC_Card Driver

and a description of the installation.

The MC_Card is an A / D board that converts analog signals in real time into digital data streams

at sampling rates of up to 50 kHz for all channels.

You configure the input voltage range from +/- 400 mV to +/- 4V and the sampling rate with the

software controls in the MC_Rack program. Please refer to the MC_Rack Help or Manual for more

information.

The input voltage range affects your dynamic range, that is, the lower the input voltage range,

the higher is the voltage resolution.

Please see the MC_Card data sheet for additional information on the pin layouts and the technical

specifications.

DC Offset correction

An offset correction is generally not necessary, because the intrinsic DC offsets of the MCS

amplifier outputs and the MC_Card are very low in comparison to the signals of interest. The

maximum total DC offset is +/– 3 mV (+/– 2 mV for the MC_Card, +/– 1 mV for the MEA amplifier

outputs). For a standard MEA amplifier with a standard gain of 1200, this results in a maximum

offset of only 2.5 μV (+/– 3 mV divided by 1200) with respect to the input signals.

You can use the MC_Rack offset correction feature to remove even this low offset and reset all

channels to zero. Please refer to the MC_Rack Help or Manual for more information.

Note: If you observe a large offset on any channel(s), you should contact your local retailer for

troubleshooting. The offset correction is not intended for removing large offsets, because the

offset correction will decrease the input voltage range.