Geophysical Company of Norway A.s.

Geophysical Company

Otto Benestad

Clive T Snook

Eldar K Lien

Paul Fredriksen

Kjell Hatteland

A device which can be used for digital signal processing, e.g. filtering of digital signals in the form of continuous bit streams that are linear digital representations of analogue signals. The device is composed by cascading individual filter sections. Each filter section comprises an integrating and multiplying unit, or units, an inverting unit or units and an adding unit or units. The device has been implemented on a monolithic integrated programmable circuit together with soft controlled solid state switches such that a preferred filter configuration may be selected by programming the circuit.

Digital signal processing device working with continuous bit streams

Transmitting information from a central receiver and recorder utilizes plural series-connected transmission modules, each connected to a respective data acquisition unit. The transmission modules are sequentially connected along plural transmission lines, at least two of which are outgoing data transmission lines for transmitting information from the central receiver and recorder to the acquisition units. At least two other lines are incoming data transmission units to the central receiver and recorder. Each transmission module has, for each outgoing line, respective line receivers, informaiton decoders, line transmitters and matrices of transmission line selectors controlled by individual information decoders, and a selector unit which ensures that a signal from a selected outgoing transmission line is transmitted to the next module on all outgoing transmission lines. At least one of the incoming data transmission lines is a spare line, the other being connected to a coupling matrix which inlcudes an input selector, a data selector, and an output selector for each ordinary line, and one output selector for the spare line. Each input selector chooses whether the transmitted signal travels via the spare line or the associated ordinary line. The data selector chooses whether the resulting signal is transmitted further or data from its own data acquisition unit enters the data stream. The output selector chooses whether the new resulting signal is transmitted further only on its ordinary line or is also transmitted further on a spare line. Each set of input selectors, data selectors and output selectors belonging to the spare line are controlled from the information decoder belonging to the selected outgoing transmission via individual multiplexers.

Data transmission system for seismic streamers

A cable for towing air or water guns behind a seismic vessel is constructed with a reinforced air hose in the center region. The air hose (1) is a Kevlar fiber reinforced high pressure air hose with low air diffusion. Outside the hose, signal conductors are placed which are individually insulated with watertight coating and arranged substantially in a single layer of cylindrical elements (2) that are wound around the air hose (1). The interstices between the elements are filled with a water-repelling lubricant. Outside the layer of cylindrical elements (2) is a protective intermediate jacket (3) not intended primarily to have a water-sealing effect, and this is followed by tension-relieving elements (4) preferably disposed in two layers twisted in opposite directions around the intermediate jacket. An outer protective jacket (5) for the entire cable can be provided on the exterior. A cable constructed in this way provides a solution of the water-sealing problem. It is especially intended for digital data transmission.

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Jar, Norway

Otto Benestad