Feasability Study of Intrinsically Digital Broadband Seismometer

The objective of this project is to design and build a seismometer that combines the essential features of a traditional pure analog seismometer, which outputs a voltage signal, with a traditional digitizer, which samples that voltage signal and provides digital word output. The design does not just physically integrate a seismometer with a digitizer. Instead, the design employs a new approach altogether. Digital delta-sigma over-sampling of the seismometer¿s mass suspension voltage occurs within the control loop of the sensor, and digital electronics are used in the control feedback path to maintain the instruments dynamic range. In theory this may provide for a system design that is more compact, draws less power, and is easier to manufacture. Furthermore, the development of this class of instrument may ultimately allow for on-the-fly changes to seismometer configuration that redefine its transfer function characteristics such as gain (ground acceleration to digital count), and frequency roll-off, providing more flexibility for a single instrument.