AS500A The 500A Microseismic Data Logger system consists
of the Microseismic Data Logger (MDL) unit and a number of transmitters. The
system provides real-time monitoring of microseismic events within a mine.
Low-noise signals are ensured by the use of a preamplifier and balanced line
driver circuit in each transmitter. Sensors can be located up to 3 kilometers
from the MDL (distance can be extended to 7 km if repeaters are
installed).