Self-calibrating seismic amplifier and telemetry system
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Abstract
A frequency modulated, constant bandwidth, telemetry system has been designed to transmit simultaneously up to 8 channels of seismograph data from remote locations to a central recording site via radio or voice-grade telephone circuit. By utilizing state-of-the-art integrated circuits, the size of the remote unit has been considerably reduced over previous equipment and the power consumption has been decreased by a factor of over 100 to less than 2 milliwatts. This reduction in size and power makes it possible to package the electronic equipment, together with a year's supply of batteries, in a container the size of a tennis-ball can. The field equipment for a short-period station is now sealed in a 3-inch plastic tube 22 inches long . The tube, together with the connecting cable to the telephone terminal, is buried; greatly reducing losses due to water flooding, pilferage, etc. An important addition to the field unit is a daily calibration of the seismometer and amplifier.
Specifications and instructions for the three units that compose the system are presented separately, as follows:
1. J302 Preamplifier and voltage controlled oscillator
2. C-4 Calibrator
3. J101 Discriminator
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Self-calibrating seismic amplifier and telemetry system |
| Series title | Open-File Report |
| Series number | 75-64 |
| DOI | 10.3133/ofr7564 |
| Year Published | 1975 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Description | 44 p. |
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