Abstract: A cellular mobile radio-telephone system incorporates hand-off equipment for effecting a hand-off of communication links coupled to a mobile subscriber transceiver as the transceiver travels from one cell to an adjoining cell. The hand-off equipment includes a filter which smoothes voice channel signals received from the mobile transceivers so as to permit a more precise determination as to when a reduction in signal amplitude indicates the need for a hand-off. The operation of the filter includes long and short term averaging of a sequence of signal samples. Circuitry is also provided for predicting a time of signal fade-out based on differences in the amplitude of successive samples or groups of samples. Also disclosed is circuitry for commanding a change in transmitter gain in a transceiver as a function of signal fade-out.

Abstract: A pulsation damper includes a housing which bounds an internal space and two substantially coaxial openings at opposite axial ends thereof. A movable wall sealingly subdivides the internal space of the housing into a fluid-containing compartment which is supplied with the fluid whose pulsations are to be damped through one of the openings, and a gas-containing compartment which communicates with the other opening. An actuating rod is connected to the movable wall for joint movement therewith and has an extension portion which extends into the other opening and has an annular recess and forms a sealed interface with the surface bounding the other opening. Two annular channels open onto such surface at axial spacings from the recess in an equilibrium position of the movable wall.

Abstract: In a loudspeaking telephone it is necessary to ensure that pick-up by the microphone of sound from the loudspeaker does not set up a howling condition. To do this it is usual to disable either the transmitting or the receiving speech channel.To do this, the signal from each channel is applied to an analogue-digital signal envelope converter (30,31), which generates a multi-bit word representative of the current speech amplitude in its channel. Those words are applied to a comparator (32) whose output is indicative of which channel passes speech. Such a converter follows the envelope of the speech signal in its channel to produce the multi-bit word representing the current speech amplitude in its channel. The comparator's output goes via control logic (33) to two attenuators (34, 35), one in each channel. Thus only the channel which is actually passing speech, or the one with the higher speech amplitude, is enabled.

Abstract: An enclosure includes a closed housing having a wall dividing the housing into a first compartment containing a high voltage portion of the power supply and a second compartment containing a low voltage portion of the power supply. A dielectric fluid fills the first compartment and partially fills the second compartment. A first check valve disposed in the wall enables fluid to flow from the first compartment to the second compartment during a temperature increase to compensate for expansion of the fluid in the first compartment. A second check valve disposed in the wall, in communication with the fluid in the second compartment, enables the fluid to flow from the second compartment to the first compartment during a temperature decrease to maintain the first compartment full of the fluid.

Abstract: The present invention consists of a multirate data receiver which will recover data at any of N data rates with no predetermined restrictions on the value of N. The data rate at which the receiver operates is selected by a single 1-of-N switch selection. An equalizer section is constructed for each of the N data rates but are all controlled by the same (common) automatic adjustment circuitry, which controls gain and frequency compensation. The output from one of the equalizer sections is selected by an analog multiplexer constructed of field effect transistor (FET) switch circuits. The recovered waveforms from the equalizer sections are processed by common circuitry to recover the transmitted data. Clock recovery may be accomplished, for example, by a digital phase locked loop constructed such that the characteristics of the loop filters and divide-by-M feedback counters are easily modified by logical signals controlled by the 1-of-N switches.

Abstract: A diaphragm pump pumping arrangement includes two diaphragm pumps which are arranged and operate in tandem. Each of the diaphragm pumps includes a housing and a movable wall that includes a flexible diaphragm and subdivides the interior of the respective pump housing into a pumping chamber and an actuating chamber. An air distributing control arrangement interposed between and connected to the pump housings includes a spool valve movable in a bore of an aluminum casing of the control arrangement between two end positions in which it alternatingly achieves the admission of the compressed air into one, and discharge of the air from the other, actuating chamber.

Abstract: The sealing element of a butterfly valve includes a rigid support ring, and an elastically yieldable sealing ring which partially embeds the support ring within itself. The sealing ring has an inner portion which is juxtaposed with the inner periphery of the support ring, and two end portions which emerge with the inner portion and extend therefrom in the radially outward direction in juxtaposition with respective axial end faces of the support ring. At least one of the end portions of the sealing ring terminates before it reaches the outer peripheral surface of the support ring, so that it exposes an annular zone of one of the axial end faces of the support ring. An annular, circumferentially complete, projection of the valve body extends into the passage at the downstream end thereof as considered in the direction of fluid flow through the passage in the fully open position of the valve member.

Abstract: A multiple-ring communication system is disclosed wherein each node of the system is adapted to collect information on the status of the system. Receiver/transmitter equipments of each of the nodes are able to transmit ring test messages on the rings, the destinations of which are the node itself. Processing equipments control the receiver/transmitter equipments of the node and are able to check the receipt or absence of receipt of the ring test messages prior to possibly executing reconfiguration operations. Receiver/transmitter equipments of each of the nodes are also able to transmit neighboring node test messages on the rings, which upon receipt by the receiver/transmitter equipments of the neighboring nodes normally give rise to the transmission to the node of node test reply messages on rings different from those on which the neighboring node test messages were transmitted.

Abstract: A check valve particularly for use in large-volume applications includes a self-contained pressing unit which is mounted on a common pivot with the valve member in the outlet compartment of the valve housing and presses the valve member towards its closing position in which it sealingly contacts the valve seat. The pressing unit includes an elongated support member and an L-shaped pressing member which are mounted on a bearing sleeve for angular displacement relative to one another about the axis of the bearing sleeve. A buckling-type spring is mounted between a free end portion of the support element and the region of merger of the two legs of the L-shaped pressing member, the spring urging the pressing component away from the support component, and against the valve member upon installation on the pivot. The spring characteristic is such that the spring force initially rapidly increases, than drops precipitously and then remains substantially constant over a substantial range of deformation of the spring.

Abstract: An improved low loss fused biconical taper fiber optic coupler has a biconical taper region where the fibers are fused together and have a deformed zone at their minimum taper region. The deformation of the fibers is in the shape of a ball.

Abstract: A pulse corrector provides circuitry for responding to first and second input pulses applied to its first and second inputs to provide first and second output pulses at the first and second outputs respectively such that the first pulse edge occurring at the first output after an interruption of the first input pulses never leads the corresponding first pulse edge occurring at the second output irrespective of the phase relationship between the corresponding first pulse edges occurring at the inputs after the interruption. Circuitry is also provided to ensure that the duration of the pulse produced at the first output and starting with the aforementioned first edge is not substantially less than that of one of the first and second input pulses, thus ensuring that a phase detector connected to the outputs of the pulse corrector is placed in a predetermined neutral state by the aforementioned pulse edges such that both its outputs are activated before reference pulses are again allowed to contact its input.

Abstract: A method and apparatus for fusion splicing optical fibres, in which the first clamping arrangement comprising arms 3 and 4 and clamps 3a, 4a pivots over from a first position to a second position in which magnetic fibre clamps 14a, 14b hold the fibre ends in a two-part fibre V-location 8a, 8b to precisely coaxially align the fibre ends. Fusion electrodes 11, 12 fuse the ends together.

Abstract: A mechanical locking device including a rotatable stem-shaped locking member for latching together a first part having a locking opening therein and a second part, by cooperation of the locking member with the opening during a rotation of the locking member, the locking member being shaped so as to be able to be pushed axially through a resilient locking hole in the second part and so as to be thereafter unable to move axially either in a forward or rearward direction, in which the first part is a rack for mounting electrical equipment is described.

Abstract: For locating faults in digital telecommunication subscriber terminations various test loops (A, B, C) are closed and checked by signals transmitted via the exchange (16). When a fault is proved to exist in the so-called C-loop, it cannot be detected whether the fault is in the subscriber line (2) or in the network termination (1). In order to be able to distinguish between the two sources of fault, and when the subscriber line (2) is in an unobjectionable state, the filter coefficients which are continuously adjusted in a recursive filter contained in the echo canceller (24) of the subscribers group circuit (17), are stored. Since, in the case of a faulty subscriber line (2), the echo canceller (24), based on the received pulse answer, adjusts changed filter coefficients, it is possible to localize the location of fault by way of comparing the continuous coefficients with the stored coefficients.

Abstract: A cable is described which has improved flame/fire and oil/abrasion resistant properties. The cable is halogen free since the conductor insulation and all sheaths are of the self-extinguishing type. A metal screen braided at an angle between 35.degree. and 45.degree. formed between the individual wires and a plane at right angles to the cable axis over a vulcanized filler sheath provides protection of the cable conductors during fires. Outermost there is placed a thin oil and abrasion resistant extruded layer of nylon.

Abstract: A swimming pool filtering system of the closed recirculatory type having a series connected strainer, pump and filter is provided with a close coupled pump drive motor having two sets of stator windings for allowing the selection of one of two water circulation rates to achieve more efficient pool water maintenance. A specific circulation rate may be manually selected or periods of selected circulation rates may be automatically programmed using a motor stator that is energized through a timer. Reduced pump speed during periods of little or no use results in substantial energy savings and a reduction of noise pollution during evening hours.

Abstract: A fiber optic direct current coupled data transmission link having a response extending to dc by using a dc coupled receiver and a modified frequency response to avoid data width distortion which allows the dc coupled receiver to work over a wide range of input signal levels.

Abstract: The improved reflection Fabry-Perot interferometer includes the conventional pair of spaced parallel mirrors have a predetermined angle with respect to an incident light beam. The improvement includes third and fourth mirrors each disposed at a different end of the first and second mirrors at a second predetermined angle with respect to a line parallel to the incident light beam so as to reduce the end losses in the two parallel conventional mirrors and to reinforce the light beam emanating from the two conventional mirrors.

Abstract: The microwave radio frequency power divider/combiner comprises a signal input/output matching network coupled between a signal input/output and a central point of the power divider/combiner. M impedance transformer sections are connected in parallel to the central point and radiate outwardly therefrom with each of the M transformer sections having a first predetermined length, where M is integer greater than one. M pairs of impedance transformers sections are provided with each pair being coupled to an end of a different one of the M transformer sections remote from the central point with each of the transformer sections of the M pairs of transformers sections having the first predetermined length. N output/input ports are each coupled to an end of a different one of the transformer sections of the M pairs of transformer sections remote from the M transformer sections. Each of the N ports are matched to a given impedance and N is equal to 2M.

Abstract: A demodulator circuit for demodulating a suppressed carrier phase modulated data input signal includes a carrier recovery circuit providing orthogonal reference carrier signals, first and second demodulation circuits for demodulating the signal with the orthogonal reference carrier signals, at least one data estimation circuit for deriving a first data estimation circuit from the demodulated signal, a second demodulated signal being delayed to obtain a signal which in combination with the first data estimation signal controls the carrier recovery circuit. The circuit further includes an automatic gain control which in response to the first data estimation and to a delayed first demodulated signal provides an AGC output signal.