|Abstract||A digitally recording magnetometer system is designed to replace the standard photographie magnetographs at geomagnetic observatories. The instrument can operate for up to 80 days without attention.
Provision is made for immunity to brief power failures. The elements D, H, and Z are derived from a 3-component fluxgate magnetometer in which ail three detectors operate in near-zero field. A simple proton magnetometer measures F. Voltages
proportional to the values of the three elements D, H, and Z are sampled in quick succession by a digital voltmeter, once per minute. Each minute, a measurement of Fis also made. The four measurements are recorded in digital magnetic tape. Each ten
minutes, the date, time, and station identification are also recorded. A strip-chart recorder produces a visual indication of the variations in D, H, and Z. The performance of the system is estimated from a comparison of hourly mean values with those
of the St. John's Magnetic Observatory.|