State-of-the-Art Digital Seismograph
Abstract
Years ago the electronics of conventional seismometers became largely digital; however, their primary sensor components have remained analog. The Volksmeter is the first bona fide fully-digital seismograph. It is a conventional pendulum (horizontal) instrument that uses the award-winning integrated circuit (AD7745) from Analog Devices, that is a capacitance to digital converter (CDC). To measure pendulum motion, this chip monitors a symmetric differential capacitive (SDC) displacement sensor array -- one form of the first fully differential capacitive sensor. The SDC-CDC package is configured to operate in a different mode than conventional seismometers. By recording pendulum position, rather than velocity, tilt response of the Volksmeter opens a new window to the world of inexpensive instrumentation. It provides a simple means to study really-low frequency spectral components of oscillatory type, called `earth hum.' Examples of benefit from these novel features will be provided, along with some history of the Volksmeter evolution from a fundamental research program.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.S14B..01P
- Keywords:
-
- 7294 Seismic instruments and networks (0935;
- 3025)