MIMdas - A little about what we do out here in the middle of nowhere...



The system is based upon single channel distributed acquisition units (DAU’s) that collect 19/24 bits (depending on
sampling frequency) of non-aliased linear data with a bandwidth of 0 - 20 kHz. This data is relayed to central
recording unit (CRU) in a recording truck, via local area network (LAN) cables. Each distributed acquisition box is
accurately synchronized and the data buffered in each unit is transmitted to the CRU at the end of each event. The
acquisition software allows interrogation of each box and can display raw data as it arrives. The data is processed on
site and field plots produced. One value of recording and storing complete time-series data is that it allows reprocessing
at later times. For controlled source surveys at least one channel is devoted to accurately monitoring the
input current from the transmitting source. This current data is then used to deconvolve the input data and
compensate for non-ideal transmitted waveforms.
The distributed system avoids multiplicity of cables attached to sensors and the inherent capacitative coupling
problems. It also means expandability as the number of units/sensors is limited only by logistics, andthe number of
available DAU’s. The data from each channel is collected simultaneously which offers considerable noise
cancellation benefits. The time series data allows simple signal processing procedures to remove cultural noise,
which when combined with selective stacking routines and other remote reference noise cancellation schemes
produces very high quality data. Considerable area or line kilometers of quality data can be captured rapidly.