Abstract: An AC coupling receiver circuit for use in a communication system comprises a comparator connected to transmission lines forming a twisted pair wire, through AC coupling capacitors, and a non-linear element connected between the transmission lines at a position close to the comparator with respect to the capacitors. When positive and negative pulses are respectively applied to the transmission lines, the voltages of the transmission lines are respectively increased and decreased to bring the non-linear element to a substantially cut-off state, thus causing the comparator output to be inverted. As the positive and negative pulses decay, the comparator output is again inverted, thus effectng signal transmission. During the application of pulses, the charge stored in the capacitors is quickly discharged through the non-linear element, whereby fluctuation of the received threshold voltage resulting from the stored charge can be eliminated even if pulse inputs are continuous.

Abstract: System for interconnecting elements of a receiving device of great length, for example a seismic streamer, comprising a plurality of data aquisition apparatuses, each of which is adapted to collect 12 separate signals generated by receiver groups distributed in the different elements.The 12 groups of separate receivers (R.sub.1, R.sub.2 . . . R.sub.12) are regularly distributed in each element (T.sub.1, T.sub.2 . . . ), forming 6 pairs of groups. A first group of each pair (R.sub.1, R.sub.3, R.sub.5) is connected to an input of an acquisition apparatus (B.sub.2). The second group of each pair is connected either to an input of another acquistion apparatus, or to inactive electric connection means (B.sub.1, B.sub.3) adapted to connect in parallel the second and the first groups of each pair.This system can be used in seismic prospecting.

Abstract: A gallium arsenide differential line receiver circuit has a first and second receiver means for receiving first and second differential input signal voltages. A pair of depletion transistor means for transforming the signal voltages into corresponding signal currents provides pull-up, and the depletion transistors have their gates operatively connected to the first and second receiver means. A pair of enhancement transistor means is operatively connected to the pair of depletion transistor means for outputting a gallium arsenide signal representation of the first and second differential input signal voltages. Positive feedback is provided for increasing the gain of the pair of enhancement transistors and is operatively connected to the pair of enhancement transistors. Shunting means is also provided for reducing hysteresis switching and is operatively connected to the pair of enhancement transistors.

Abstract: An interactive cable television system for serving a plurality of user locations in a service area divided into a plurality of service regions, including a central office and a service network having a portion composed of parallel cables arranged in a tree pattern possessing a plurality of nodes remote from the user locations and, in the vicinity of the users, a further portion representing the lowermost plane of the network and composed of transmission cables connected to groups of user locations, the transmission cables being connected to each group in a star pattern, the system presenting a plurality of transmission paths and permitting multiple utilization of the paths, the parallel cables of the first mentioned portion of the network being connected in each service region in a tree structure extending from one node toward the user locations and being constituted by two parallel autonomous sets of cables, thus representing medium planes of the network, the network further including, in each service region