Joint Experiment on the Spectrum of Earthquake Sources - Long Period Instrumentation
Semi-annual technical rept. 1 Apr-30 Oct 1972
WASHINGTON UNIV SEATTLE
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The report covers the design, construction and testing of a prototype long-period seismograph system using digital telemetry. The system makes use of gain ranging amplifiers to obtain a dynamic range of 106 db. Using Geotech SL 210 seismometers, a magnification of 15,000 is obtainable in the pass band .05 - 1.0 Hz. The system noise in this band is 0.1 microvolt rms. The output is a frequency shift keyed tone FSK which is telemetered over VHF radio and telephone lines and recorded in direct mode on a tape recorder. A decoding system converts the serial FSK data back to parallel digital data compatible with a mini-computer.