Abstract: A two stage, decentralized device for transmitting seismic data information from seismic receivers of a seismic streamer to a central recorder on a ship, including a series of interconnected sections each having a plurality of seismic receivers distributed over it's length, seismic signal acquisition apparatus for digitizing and storing seismic signals coming from a group of seismic receivers to which a respective seismic signal acquisition apparatus is connected, central control and recording device on the ship and assembly of electronic modules each disposed in the vicinity of a seismic receiver and being capable of amplifying and filtering the seismic receiver signals.

Abstract: A device is provided for amplifying and sampling signals in an acquisition chain before application thereof to an analog-digital converter and in particular multiplexed signals. It includes two blocking samplers to which a gain of 1, 2 or 16 for the first one and a gain of 2 or 16 for the second one may be applied by selective closure of switches. A switch allows either the input signal or the signal from the second sampler to be applied to the first sampler. Another switch allows the outputs of one or other of the samplers to be connected to the input of a voltage comparator. By a very limited number of comparison steps, gain modifications and possible relooping of the output to the input of the device for one or more reamplifications, an input signal may be given any gain between 2.sup.0 and 2.sup.13.

Abstract: A device is provided for amplifying and sampling multiplexed analog signals so as to give them an optimum level before digitization thereof. It includes several amplification and sampling assemblies with fixed gains differing from one to another, an amplifier whose gain is able to take on several predetermined values, connection means for selectively connecting one of the assemblies to said amplifier, comparison means comparing the amplitude of the signals at the output of the amplifier with threshold voltages and a selection member for choosing the assembly and the gain of the amplifier as a function of the comparison. In each of the assemblies, the amplification function is provided either by amplifier stages and/or by sample and hold units.