Globe Universal Sciences, Inc.

Gus Manufacturing, Inc.

Wesley L Joosten

Carl F Mart

Otice E Brown

John W Miller

A seismic telemetry system employing frequency division multiplexing techniques is disclosed. Analog seismic data are received by remote data acquisition units (RDAU's) converted to digital form and stored in the RDAU's. The data are transmitted via a transmission line to a central station for recording. The RDAU's are connected at randomly selectable locations along the transmission line. Either an RF command or digital strobe signal is used to interrogate the RDAU's from the central station. Each RDAU responds on a separate RF carrier frequency, modulated by the previously stored digital data. The data from each RDAU, therefore, need not be separated along the transmission line from the data received from other RDAU's. At a central station, the data signals are demultiplexed and recorded. Use of high-impedance transmitters and receivers permits the transmission line to operate in flat-line mode. Elimination of the previous requirements for data separation along the line permits significantly increased data rates to be handled.

Frequency division multiplex digital seismic telemetry system

A seismic communications system including a central control and recording station and a plurality of remote data acquisition stations, the stations being approximately in line and connected to each other by one or two transmission lines. One line is all that is necessary if the central station is at one end of the line of stations; however, if the central station has some acquisition stations upstream and some downstream therefrom, two lines are required. Coded central strobe bursts put on a transmission line at the central station successively cause insertion of digital seismic data from successively more remote acquisition stations, the data being time slotted after each central station strobe burst so that reverse transmissions do not interfere with subsequent signal propagations emanating from the central station. Twin lead is preferably used for the transmission lines. Power shut down, except for a pilot receiver, is accomplished at each acquisition station between recording cycles.

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El Paso, TX, United States of America

Wesley L Joosten