Abstract: A relay station utilizes the frequency hopping principle for the purpose of protection against intentional interference. Normally, the frequency hopping range available cannot be utilized for the frequency hopping operation because an indispensable minimum signal-to-noise ratio must be observed between the receiving frequency and the transmitting frequency of the relay station. In order to eliminate this disadvantage, the transmitter of the relay station is synchronized to the receiver by way of an interface connection and, with the aid of this synchronization, the desired frequency hopping in the entire available frequency hopping range for the transmitter and the receiver of the relay station can be controlled pursuant to observation of the required minimum signal-to-noise ratio.

Abstract: An identification of friend from foe (IFF) device is described containing a radio transceiver (F) which, in addition to being designed for communication purposes, is equipped for transmitting, receiving, and evaluating IFF signals. The IFF device further includes a laser transmitter (LS) and an optical receiver (LE) which are coupled to the radio transceiver (F) via a controller (G). For identification, unmodulated direction-selective light signals and modulated nondirectional radio signals are used.

Abstract: In radio operation in tactical use, an increased jamming resistance with respect to intentional jamming is required. For protection against intentional jamming, frequency hopping techniques have proven very advantageous in which the signals are transmitted in the form of successive error-protected signal blocks where each signal block is transmitted on a different radio carrier frequency which changes in a pseudo-random manner. With this technique, phase shifts can occur which are greater than half a bit and therefore make analysis of the signal blocks difficult or impossible. It is proposed herein that each received signal block be checked after regeneration in a regenerative repeater, controlled by a bit clock pulse, as to its correct block phase and therefore, respectively, newly establish the block clock pulse phase required for further accurate processing of a signal block.

Abstract: An access device at a public communications terminal enables an authorized user to gain access, via a connecting device, to an integrated services digital communications network. The access device includes a connecting device (2) behind a protective member (4) which permits access only after a check of the user's access authorization and a test of the correct functioning of the connecting device.

Abstract: A control circuit bipolarly controls the stator of a 4-phase brushless DC motor in which the staor windings are connected in a ring circuit with only four semiconductor switches. Also, two control sequences are possible: a first control sequence consisting of four switching events per revolution and number of pole pairs, in which only two semiconductor switches are activated at a time, and a second control sequence consisting of eight switching events per revolution and number of pole pairs, in which alternately two and three semiconductor switches are activated simultaneously.

Abstract: Receivers for bandspread signals have a carrier PLL (20) for the carrier frequency and phase and a code PLL (20, 30 . . . 34) for the code frequency and phase. To be able to receive even very noisy signals, the carrier PLL, in particular, must have a very narrow bandwidth. This results in a very narrow capture range.According to the invention, instead of employing a complicated search strategy, advantage is taken of the fact that the code PLL locks in more easily. A signal is taken from the code PLL which indicates the difference between the desired value and the actual value of the code frequency. This signal is fed as an additional control signal to the carrier PLL.

Abstract: A circulation fan for circulating air in the baking muffle of an oven in which a conductive connection is made between the drive shaft and the back wall of the baking muffle whereby the RF energy passing outward over the surface of the drive shaft is short-circuited via the back wall of the baking muffle. The conductive connection is in the form of a spring element, e.g. a clamping member or a disk spring, whereby manufacturing and operational variations are compensated for. If the portion of the drive shaft located outside the baking muffle is roughened and/or covered with an electrically poorly conducting coating, further damping of the escaping RF energy is obtained.

Abstract: A transmitting station for a navigation system with dual transmitters (20A, B) is disclosed in which the dummy load, which commonly trerminates the active-standby transmitter instead of the antenna system, and the associated high-performance changeover switch are omitted. Instead, the two transmitters are operated in constant alternation. This permits better monitoring with less costly and complicated equipment.

Abstract: For a digital communication system comprising a plurality of repeaters between two terminals from one of which the repeaters are to be selectively controllable for fault-location or remote-control purposes, repeaters are disclosed each of which has its address stored unalterably in its address memory, so that the address resembles a serial number as is commonly used as an equipment identification. This saves any adjustment work during the installation of repeaters into the communication system. Also disclosed is a fault finder for such a communication system which is capable of successively interrogating the repeaters in the system for their addresses and their locations in the system, and of writing these addresses together with the associated locations into a memory. The repeaters then contain suitable devices which cooperate with this fault finder.

Abstract: A pulse generator having a plunger for actuating several contacts. The plunger is guided in a housing and is slidable in the direction of and rotatable about its longitudinal axis against the action of a spring and is provided with at least one actuating member capable of entering into non-positive engagement with at least one contact both in at least one of its longitudinally adjusted positions and in at least one of its rotated positions. The plunger has a hole which runs parallel to the direction of sliding and contains a second plunger which is slidable and/or rotatable against the action of a spring associated therewith. There is an actuating member on the second plunger.

Abstract: The antenna has a main reflector (1), a subreflector (4a, 4b, 5a, 5b), and a feed radiator (2) which are all rotationally symmetric about a common axis (10). In a section in the direction of this axis of symmetry (10), the subreflector has the shape of two curves meeting in the axis of symmetry. Seen from the feed radiator, these curves are concave. Each of the two curves has at least one step (6a, 6b) for matching the feed radiator to the transmitter or receiver.

Abstract: A method of producing polarization-maintaining single-mode optical waveguides is provided wherein the preform from which the optical waveguide is produced consists of a tube, a rod of core and cladding material centrally disposed in said tube, and two differently doped pairs of filler rods disposed about said rod, the two rods of each pair being disposed diametrically opposed to each other with respect to said rod. Maximum polarization maintenance of the optical waveguide being produced is achieved by choosing the diameter ratios so that each filler rod rests against the central rod, against the inside wall of the tube, and directly against the two filler rods of the respective other pair.

Abstract: A pulse generator is disclosed comprising a toothed disk which is rotatable with a rotary shaft and is capable of actuating at least two contact pairs for generating pulses and for sensing the direction of rotation of the rotary shaft via a rocker engaging the teeth of the toothed disk by means of a mating portion, the rocker being deflectable in different directions depending on the direction of rotation of the rotary shaft, the mating portion being movable out of engagement with a tooth space and into engagement with the following tooth space, and at least one contact spring of each contact being capable of being actuated in the range of the maximum deflections and prior to the return movement.

Abstract: In a flat picture-reproducing device having a phosphor-coated faceplate (1) and a tray-shaped rear housing (2), a cathode formed by a periodic array of heating wires (7) is provided. This heating-wire array is followed by layers of focusing wires (8) and attracting wires (9) and by a perforated anode (5). A segmented counterelectrode (6) is located behind the heating wires (7).

Abstract: The introduction of liquid-crystal material into a liquid-crystal cell is simplified by cooling the liquid-crystal material until it has a paste-like viscosity suitable for printing. After a spacer has been positioned on a first substrate, the liquid-crystal material is introduced within the interior portion of the spacer using printing techniques. A second substrate is then placed on the spacer, and the display is sealed.

Abstract: A pulse generator with a pin-shaped switching plunger for actuating at least one contact is so designed that many switching positions are possible. It is characterized in that the switching plunger (3), which is guided in a housing, is slidable in the direction of and rotatable about its longitudinal axis (5), and that the switching plunger (3) is provided with at least one actuating member (4) which can enter into nonpositive engagement with at least one contact (2.1 to 2.8 and 1.1 to 1.8) both in any of the longitudinally shifted positions and in any of the rotated positions.

Abstract: A flat-type polarized relay with contact springs disposed at the sides of a parallel to the coil system. A magnetic core projects beyond the coil form and cooperates with movable pole plates disposed together with a permanent magnet in a transversely movable cross slide. The magnet yoke is a U-shaped member made from flat material. The base of the yoke is rigidly connected with the magnetic core, and the legs run along the sides of the coil. The relay has a small overall height and a high switching capacity at small energizing currents.

Abstract: In the basic configuration of the microwave landing system, an azimuth station (2) and an elevation station (1) are interconnected by a data link for transferring data and sync signals, and each of the stations includes a monitoring facility (10, 15; 3, 8) for monitoring its signals in the near field. In the novel microwave landing system, the near-field monitoring facility of one of the stations is also used to monitor the signals from the other station in the far-field.

Abstract: A circuit arrangement including a controllable optical resonator having a filter characteristic with a transmission peak arranged to pass laser radiation at a wavelength in the region of the transmission peak, wherein the resonator is positioned to receive the laser radiation at an angle such that two modes of the radiation, having respectively different polarization states, and wavelengths, are capable of propagating in the resonator. The resonator has control electrodes connected for receiving a voltage which determines the wavelength of the transmission peak of the filter characteristic and a source connected for applying to the electrodes a square-wave modulating voltage which varies between a first value which causes the transmission peak of the resonator to be substantially at the wavelength of one of the modes and a second value which causes the transmission peak of the resonator to be substantially at the wavelength of the other one of the modes.

Abstract: A frame-supported fan in which the mounting portions between the motor and the frame are formed in the shape of an arrowhead and/or are provided with sculptured edges extending to the frame or are provided with interfering bodies mounted to the outer ends of the edges of the frame, so as to reduce unwanted noise by producing non-uniform flow separation in the air stream through the fan.