Use the DTU100 Digital Trigger Unit to trigger an MRI system with the occurrence of the R-wave present in animal (high frequency) ECG or respiratory data for gating purposes. This external hardware module can accept data from any analog output associated with an MP system and convert that analog signal into a TTL compatible trigger suitable for synchronizing with external devices; the DTU100 is always used with the HLT100C module.
For the DTU100, "analog output" means:
Analog output associated with any MP module (DA100C, ECG100C, etc.) that is sending data to an MP System on analog input channels 1-16.
Analog output coming from the MP system via one of its D/A converters on analog output channel 0 or 1.
The DTU100 provides high-level (3,000 V) isolation between the MP System and external equipment. This isolation is very important to maintain both subject safety and high-quality signal recording.
HLT100C
The DTU100 is always used with the HLT100C module. Use the RJ-11 straight through cable provided by BIOPAC to plug the DTU100 into the HLT100C.
Feedback Views
The DTU100 incorporates three feedback outputs that can be monitored on the MP System to properly set the threshold (trigger) level and required Trigger Out polarity for any type of analog input. Use a 3.5 mm mono phono cable (CBL100) to connect the respective line to an unused MP system input channel.
Threshold View—shows the Threshold (Trigger) Level
Trigger View—shows the Trigger Output as sent to the external equipment.
Signal View—shows the analog input signal as sent to the DTU100.
Trigger Out Connect a TTL line with BNC female connector between the DTU100 and your trigger device.
Normal/Auto Level The DTU100 incorporates an optional Automatic Level control circuit. The Automatic Level control circuit will expand or compress the analog input signal to fit inside of a ±5 V range.
If the analog input signal is clearly defined, run the DTU100 in Normal mode.
If the analog input signal has a widely varying baseline or significant change in amplitude from one desired trigger point to the next, consider operating the DTU100 in Auto Level mode, or try to improve signal definition.
Trigger The Trigger LED (green) will light up whenever the Trigger Out signal goes high.
Positive/Negative If analog data is above the threshold setting, the DTU100 output can be set to either high (+5 V) or low (0.0 V). When analog data drops below the threshold value, the output will be the opposite level.
Trigger Level Select a trigger level (or threshold) that will fire when analog data reaches that threshold.
High-level output transducers and adapters connect to the HLT100C via standard 6 pin RJ11 type connectors. Transducers and adapters that presently require the HLT100C module are:
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