Abstract: A ferro-electric liquid crystal display in which the individual pixels are addressed via an address matrix that includes one field effect transistor for each pixel, and a plurality of row and column conductors whereby data is written into each pixel to change or to maintain its display condition.

Abstract: A fiber optic cable includes layers and elements for mechanical and fire protection of the cable, all having the same or substantially the same thermal coefficient of expansion as the optical fibers. The fiber optic cable core is protected against flames by at least two layers of mica separated by a layer of synthetic material.

Abstract: Prism couplers are manufactured by disposing a prism (10) on an optically flat waveguide (11) such that the region therebetween is shaped for substantially optimum coupling of optical energy therebetween, and securing the prism to the waveguide without deformation of the waveguide. The prism may have a curved, for example part-cylindrical, base (FIG. 4) or be separated from the waveguide by appropriate spacers (FIGS. 5 or 6). The prism may be secured to the wavegudie by an optical epoxy compound.

Abstract: An integrated communication system (e.g., BIGFON) includes the narrow-band telephone network and a superposed video-telephone network. The path search for setting up calls in the telephone network is carried out with the aid of the telephone call numbers. To permit a video-telephone network structure independent of the structure of the telephone network, each subscriber of the video-telephone network must be assigned a separate video-telephone call number for the path search in the broadband network. In order that a subscriber does not have to dial two different numbers to set up a video-telephone call, each exchange (V1, V2) of the communication system includes a mapping circuit (ZS) which establishes for each video-telephone subscriber (TEA, TEB) a correspondence between his or her telephone call number and a video-telephone call number serving to set up calls in the video-telephone network. This video-telephone call number can be called up from the mapping circuit (ZS) via the telephone network (FN).

Abstract: The time required for several calibration signals to traverse a signal path (1, 2, 3) is determined and compared with a nominal value. The individual calibration signals have different values for at least one signal parameter. Depending on the results of the comparison, a control signal is produced for each value of the signal parameter. Of the intelligence signal, the value of the signal parameter to be taken into account in the determination of the control signal is measured prior to the traversal of the signal path, and the control signal assigned to this value is selected.The control signal can be used in DME transponders to set an exact transponder delay, and in DME interrogators to allow for delay variations in the distance measurement.

Abstract: A communication terminal for processing voice and graphical information having a telephone set including a handset supported by a housing with an input device mounted within the housing for establishing communication with a distant terminal. The input device includes a flat display screen having a presentation portion and a switching field portion. A transparent resistive coating which conducts electrical signals and which is mounted over the presentation portion is manually contacted by a pen which extracts a signal for identifying the point of contact. The pen is used to touch the portion of the screen representing a dial keypad and various switching functions. The extracted signals are digitized and transmitted to distant terminals via a control circuit which processes both voice and graphical information.

Abstract: A transparent glass article, e.g., for use as an inspection window in contact with water, including at least a surface layer of a glass which is adapted to dissolve at a preselected uniform rate. Slow dissolution of the glass provides a continuously renewable clear surface.

Abstract: A sensor for magnetizable materials is comprised of an inductive component and an evaluating circuit. The inductive component is constructed by thin-film techniques. The core is made of a ferromagnetic amorphous metal. Such a sensor can detect the presence of magnetizable materials with very high position accuracy. The sensor is employed in revolution counters and in angular-displacement transducers.

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: 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: 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: 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: 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: 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 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: 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: The invention concerns a centrifugal pump for pumping heavily polluted liquids. The impeller is provided with an inlet having cutting means cooperating with an inlet opening of the pump housing, which cutting means cut elongated bodies, such as rags before they get into the pump housing.

Abstract: A telecommunication switching system includes a number of control circuits each of which is common to a plurality of line circuits and is coupled through time division multiplex links with two processor controlled interface circuits which are further coupled to a switching network. Line scanning information is processed in the control circuits to reduce the work load of the processor controlled interface circuits. Said line scanning information is then transmitted in the TDM links to the processor controlled interface circuits. The transmission priority among the control circuits is determined by a priority arrangement established for the system. A channel assignment controls the allocation of channels of the TDM links leading to parts of the line circuits.

Abstract: A TACAN beacon is disclosed in which the pulse-modulated carrier signal generated in a transmitter is applied to the elements of a circular antenna array through controllable phase shifters that generate 15-Hz and 135-Hz sidebands through, switches, and through a Butler matrix. A switching facility generates two states. In the first state, the phase shifters are controlled to generate the upper and lower 15-Hz sidebands and the upper 135-Hz sideband, respectively. In the second state, they are controlled to form the respective opposite sidebands.The Butler matrix generates, radio-frequency phase-rotation fields at the antenna. In the two states, the ordinal numbers of the radio-frequency phase-rotation fields differ in their signs. The absolute value of the largest ordinal number is smaller than or equal to six, and the sum of the absolute values of the ordinal numbers for the carrier signal and the upper or lower 135-Hz sideband is equal to 9.

Abstract: In a local area network (LAN), of the Ethernet type, one of the segments, i.e. one bus, is replaced by a star coupler connected via optical fibre pairs to a number of stations. Each pair includes a GO fibre and a RETURN fibre. As in the usual Ethernet system, collision detection relies on measuring signal level on the medium, if it is too large then a collision condition exists.In an optical fibre system a similar collision detection technique is used. To detect collision, it is nescessary to be aware of the network's attenuation as "seen" by the station. To do this a low level pilot tone is sent from each station, each station having its own tone frequency. The amplitude of this tone when it returns to its own station indicates the system's attenuation, and this is used to detect collision.In an alternative the pilot signals are pseudo-random bit sequences.