Multichannel Systems Portable_ME-System Manual - Manual (Page 25)

System Components
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Example:
You have a broadband filter amplifier with a bandwidth of 1 Hz to 5 kHz. The expected signals have
a maximum frequency of 1 kHz. Therefore, you want to filter the data with a digital low pass filter and
a cutoff frequency of 1 kHz. A sampling rate of 5 kHz (five times the highest signal frequency) would
be required for faithfully reproducing the signals, but you should use a sampling rate of at least 10 kHz
because the sampling rate should equal twice the bandwidth of the analog filter, regardless of the digital
filter properties.
If you had an amplifier with a cutoff frequency of 1 kHz instead, no digital filter would be required, and
a sampling rate of 5 kHz would be sufficient.
Software Package
With the high-performance data acquisition and analysis program MC_Rack, you can flexibly manage all
data streams. For example, you can display the raw data of all channels while recording only the raw data
of the channels of interest and the extracted parameters of all channels. This saves computer performance
and hard disk space.
MC_Rack is not limited to special applications, but can be flexibly adapted to a wide range of applications.
The ".mcd" data format is supported by several third party programs for further analysis. You can also
easily convert recorded data to universal formats such as ASCII with the MC_DataTool program.
6.3 Digital Input / Output, System Synchronization
TTL stands for Transistor-Transistor Logic. A TTL pulse is defined as a digital signal for communication
between two devices. A voltage between 0 V and 0.8 V is considered as a logical state of 0 (LOW), and a
voltage between 2 V and 5 V means a 1 (HIGH).
See "Digital IN / OUT Connector" in the Appendix for information on the pin layout.
Warning: A voltage that is higher than +5 Volts or lower than 0 Volts, that is, a negative voltage,
applied to the digital input would destroy the electronics. Make sure that you apply only TTL pulses
(0 to 5 V) to the digital inputs.
Triggering MC_Rack
The digital input accepts TTL pulses. This feature can be used for triggering MC_Rack, for example,
for synchronizing stimulation and data acquisition.
For example, you can connect the Sync Out of a STG (stimulus generator) to one of the digital input bits.
If you use only one instrument for triggering, connect it to bit 0, for example. In MC_Rack, add a Trigger
Detector to your virtual rack, and select the "Digital Data D1" input stream as the Trigger. Select the
appropriate logical state (generally HIGH) for triggering. Mask all unused bits. The standard settings of the
Trigger Detector are for using bit 0.
Please see the documentation on the Trigger Detector instrument and on triggered data in the MC_Rack
help or manual for more details.