A DIGITAL MAGNETOMETER SYSTEM USING CONVENTIONAL VARIOMETERS AND OPTO-ELECTRONIC CONVERTERS

At the magnetic observatory of Fuerstenfeldbruck, conventional variometers were equipped with low cost opto-electronic elements which convert the angular movements of the recording magnets to electrical signals so that automatic data processing is possible. The feedback loops used raise the resonant frequencies of the variometers so that a wide frequency band ranging from pci pulsations down to d.c. is covered. The magnetometer system is connected to a multi-channel analog-to-digital converter with 13 bit resolution. The AD converter is controlled by a microprocessor via an optical isolated serial link for recording digital minute values. The long-term stability of the system is at least as good as that of a high quality classical system with photographic recording. © 1990.