Guralp Systems CMG-DCM build <10,000 User Manual
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Acquisition Modules and Platinum Firmware
Preliminary Notes
1.5
A note on terminology
Scientists and engineers from different disciplines often use different
terminology to describe similar concepts. The following terminology is used
consistently throughout this document.
1.5.1 Sensor
A “sensor” is an accelerometer, velocimeter or other transducer (e.g.
geophone or hydrophone) with an analogue output - i.e. where a
continuously varying voltage is used to represent the magnitude of the
quantity being measured.
A sensor cannot generally be used as a standalone component: it forms a
sub-assembly of an instrument (see below).
1.5.2 Instrument
An “instrument” is the assembly of sensors, control
electronics, casing and connectors. An example of an
instrument is the CMG-3T seismometer shown on the
right.
A digital instrument is one that combines one or more
sensors with a digitiser; their part numbers include a 'D'.
A 3TD, for example, is a 3T instrument combined with a
DM24 digitiser.
Within this document, the term “digital sensor” is used in
two contexts: when discussing digital inputs (which may be connected to
either digitisers or digital sensors) and when describing configuration items
which apply to both the digitiser modules embedded within digital sensors
and to stand-alone digitisers.
1.5.3 Digitiser
A “digitiser” is an electronic device designed to accept
analogue inputs from one or more sensors and, using
sampling techniques, convert these analogue signals into
streams of numerical data, which are then stored or
transmitted digitally.
An example of a digitiser is the CMG-DM24 shown in the image above.
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Issue E - February 2014