Abstract: A frequency hopping data communication system for a bidirectional communication system is described in which improved operation in a jamming and/or fading environment is provided. A pseudo-noise code generator is utilized to provide a random sequence of ON-OFF pulses representative of binary numbers which cause a microprocessor to select data at a desired frequency which is then coupled to a frequency synthesizer to provide a controllable frequency and an improved anti-jam capability in both a receiver and transmitter.

Abstract: A laminated electrical heating foil element includes electrical resistance strips embedded between two sheets of insulation material to make the laminated heating element with its power supply terminal. The heating element is in particular adapted for horizontal floor mounting between adjacent floor joists, and each element may either be wider than the specified joist distance by approximately 2h, where "h" is the specified minimum distance to be left free above an installed element, or each element may be provided with fastening devices which may cooperate with complementary catching devices on the joists. Different fastening devices between joist and heating element, as well as easy-to-fold zones running along both side edges of the heating element, are included.

Abstract: The cable core containing one or more optical waveguides is protected from longitudinal and transverse forces by being loosely disposed within a sheathing. The sheathing consists of a tubing which is divided into two sections in the longitudinal direction. Following the placement of the cable core in one tubing section, the latter is closed by placing the other tubing section thereon, in such a way that the two tubing sections are thereafter inseparably connected to one another.

Abstract: A telephone subset with a desk and wall mount capability employs an east-to-west oriented handset. The subset base has a bearing at a first axis on which the subset housing pivots. The base has slots for the tabs of a bracket to engage and hold the subset in the desk or wall positions. The housing provides a cylindrical well in which a spring loaded pin is mounted, and also provides surfaces on which the subset handset cradle, which houses the hookswitch, rests in the desk and wall configurations. To prevent the bracket from translating, the spring loaded pin engages a hole in the bracket. As the pin is depressed, it disengages the hole and allows the smaller diameter section of the pin to enter the slot so the bracket can translate. The bracket provides an axle on which the cradle mounts, forming a pivot at a second axis, for pivoting from a desk position to a wall position.

Abstract: An arrangement for splicing two optical fibers together includes a tube into the respective ends of which each of the optical fibers is inserted. The tube has an eliptical cross-section. The tube is also curved and has an approximate 15.degree. arch along its major axis. This construction results in self alignment of the fiber ends in both a vertical and a horizontal direction. A housing is either formed with the tube in a one piece unit or is subsequently positioned around the tube after the optical fiber ends are spliced. An optical adhesive material may be inserted into the tube and sleeve to prevent light transmission loss due to Fresnel reflections.

Abstract: An optical receiver of the so-called high impedance type has a photo-diode onto which the modulated light beam from an optical fiber, or received via free space, falls to produce a current in that diode. One end of the diode is coupled directly to the gate of a FET, the other end of the diode being coupled via a capacitor to the source of the FET. The FET's source and its bias resistor are on a source-connected pad. The source output of the FET is coupled via an emitter follower impedance buffer and an equalizing capacitor to a broad-band amplifier. Thus the receiver has a flat overall in-band response.

Abstract: A voice-controlled hands-free facility contains a microphone, an internal and an external loudspeaker, and two series combinations of an input amplifier (EV), a variable attenuator (DR), and an output amplifier (AV), one for the send path and one for the receive path, and is controlled by a voice control unit (SS) connected to the output (E) of the input amplifier (EV), to the output (D) of the variable attenuator (DR), and, by a line (L), to an input of the variable attenuator (DR).To permit the hands-free facility to be switched from a single-part mode of operation to a two-part mode, the output (E) of the input amplifier (EV) in the send path and/or the receive path is connected to the output (A) of the output amplifiers (AV) through a bypass device (BP) and a switching unit (T).

Abstract: An optical fibre Fabry-Perot etalon can be used as a sensor if the parameter being monitored is allowed to influence the etalon's length, e.g. by pressure, temperature, magneto-strictive effects, piezo-electric effects, acoustically, etc. However, with single-mode fibre and only one set of peaks in the transmission function the device is direction insensitive so that the sign of the parameter being monitored cannot be detected.In the present arrangement the etalon is driven in such a way as to support two different path-length distinct transmission modes, e.g. by the use as a light source of a laser emitting light at 1.3 micrometers wavelength. Two sequences of peaks are then produced in the transmission function which are peaks of different sizes, so that the transmission function is asymmetrical. The peaks are separated at the detection circuitry by discriminations followed by pulse counting means so that the arrangement becomes sign responsive.

Abstract: The mobile radio set has a rectangular parallelepiped-shaped case suitable for mounting in the dashboard of an automobile. The handset can be locked at its earpiece and mouthpiece into a cradle mounted on the front panel of the case so that the handset can be positioned in a rest position across the front panel. The keys, mounted on the side of the handset facing away from the cradle, are readable and operable in the rest position of the handset. With a lock mounted in the handset, the mobile radio set can be deenergized and the handset can be blocked in the cradle.

Abstract: A volume control device suitable for installation on the ringer of a telephone incorporates a tone control lever having a damping element cantilevered therefrom and extending as a wing from a point of pivoting in a direction generally parallel to a frame of the ringer. The lever further comprises an arm bent through the frame to serve as a handle, and a leg extending in an opposite direction from the pivot for contacting a detent structure integrally formed with the frame. Also, integrally formed with the frame, are a ramp and a guide. The guide extends upwardly from the frame and then over a path of travel of an outer end of the wing for urging the wing downward so as to ensure passage of the wing underneath a rim of the gong during a rotation of the lever about the pivot.

Abstract: In the novel equipment for the stereophonic sound reproduction in the television receiver all essential components, such as loudspeakers, crossover networks, etc., are accommodated in one single enclosure which fits into the space above the picture tube, in which it is mounted.

Abstract: In the standard DME system, an airborne station having transmitted a pair of interrogation pulses receives a plurality of pairs of space-coded reply pulses from which the pulse pairs intended for the airborne station are selected by a decoder (DK) and a correlator (KR).The invention uses the first pulse of the selected pulse pair for the distance measurement. A measuring counter (MZ) is provided whose count is transferred to a register file (SR) at the reception of every pulse. A reply signal intended for the airborne station stops the write operation, it being insured that the counts based on the two pulses of the reply signal intended for the airborne station are contained in the register file (SR). Starting from the last count based on the second pulse, an evaluating circuit calculates back to the first pulse, taking account of the decoded pulse spacing.

Abstract: In a loudspeaking telephone the power supply to the loudspeaker amplifier is shunted by a regulator which functions as a programmable Zener diode. Under conditions of low available line current, e.g. where two similar instruments are operated in parallel at the end of a long line, the regulator voltage is reduced in value to disable the amplifier and conserve power to maintain the basic operating functions of the telephone.

Abstract: Armored submarine power cables are designed for laying in waters with varying depths. The cable has an armor which is heavy and strong (steel wires) in shallow water sections. In very deep waters the weight of steel armor is prohibitive so that in these sections the armor is made of synthetic light weight material. The transitions between the two types of armor are made physically concentrated but flexible enough to prevent sharp bends of the cable core as it passes cable laying machinery. The armor joint may be displaced from cable core joints and substantially effectively transfers all longitudinal strain in the cable.

Abstract: In a push-button switch, the switch element is a cantilever (2) of thin silicon strain gauge material with a small magnet (1), e.g. of samarium cobalt alloy at its free end. Adjacent to the free end there is an annular magnet (3), e.g. of plastics material impregnated with samarium cobalt alloy, on the push rod (4) of the switch. The annular magnet (3) is so poled that movement of the rod (4) causes, due to magnetic forces, the deflection of the silicon strain gauge to give an electrical output.The return force, plus collapse action, is provided by a soft iron collar (5) on the switch structure.

Abstract: An optical receiver which consists of an optical attenuator, an optical-to-electrical transducer, an amplifier, and an automatic level control circuit. The optical attenuator is an electrooptical modulator which is electrically controlled by the automatic level control circuit.