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: To measure absolute rotations in several directions in space with the aid of interferometers, one interferometer is required for each direction in space. According to the invention, it is proposed to supply a device consisting of several interferometers from a common light source and to switch only the phase modulation impressed on the light rather than the light paths, using time-division multiplexing. The output signals from the interferometers are detected and evaluated with a single detector and evaluating unit.

Abstract: A method of determining a temporary subscriber number (TMSI) in a subscriber data base is disclosed. Subscriber data bases with large subscriber-data fluctuations require special strategies to ensure optimum utilization of the available storage space while keeping access times as short as possible. In addition, subscriber anonymity is to be ensured. A method is provided for assigning a memory location to each subscriber via a temporary subscriber number (4-byte TMSI). The invention uses an internal structure for the TMSI which consists of several logically independent elements which, on the one hand, permit as large an addressing range as possible and, on the other hand, preclude any confusion of data records or any identification of the subscriber. In addition, the TMSI is constantly changed. With a 32-bit TMSI, up to 10.sup.6 subscribers can be unambiguously addressed.

Abstract: A switching device for being connected to switch optical input signals received on a plurality of optical input signal lines into optical output signals on a plurality of optical output signal lines; each device has a time slot interchanger or a wavelength converter in combination with a space-division switching stage for freely exchanging signals on different lines, wherein, according to the invention, such a switching device has multiple stages, including both a time slot interchanger stage and a wavelength converter stage in combination with two space-division switching stages and wherein between every two of the space-division switching stages a time slot interchanging or wavelength converting stage is inserted; the time slot interchanger stages may alternate with wavelength converter stages with a space-division switching network stage in between.

Abstract: Method for acquiring network knowledge in the individual operating locations of a digital transmission network having a plurality of network nodes.Following a computer outage, digital signal connections set up via central computers can no longer be reconstructed within the individual network nodes, so that no emergency operation is possible.The method is intended to place every participating network node into the position of maintaining the original or momentary path of the digital signal connection given computer outage or to restore it or, respectively, to independently set up or alternately route a connection.At the start of the digital signal connection, the digital signal is provided with an identifier in every transmission direction in the transmitting network node, this identifier being supplemented in every following, through-connecting and terminating network node. This identifier can be evaluated in each of these network nodes.

Abstract: In contrast with conventional transmitting stations for a position locating system in which the main equipment and the standby equipment operate alternately and are monitored by checking the transmitted signal received from external sensors, the present invention monitors at least the standby equipment during inactive periods during which no signal is being transmitted. In a preferred embodiment, external sensors (FS, MF) are provided for monitoring both the main transmitter (TXM) and the main timing and control section TCS1) during transmission periods, a dummy load (DL) and an internal sensor (IS) is used for monitoring the standby transmitter (TXR) during non-transmission periods, internal monitoring information (MI) is used for monitoring the reserve timing and control section (TCS2) and the electronic antenna (EA), and the two monitor sections (MS1, MS2) contained in the monitor unit are used to monitor each other.

Abstract: A fiber-optic gyroscope for measuring rotation rates which includes electrical, optical, and electro-optical functional units as well as at least one fiber coil, is constructed so that at least the optical and electro-optical functional units are integrated on a single silicon substrate.

Abstract: Landing aids using phased-array antennas must be very carefully calibrated. Conventional methods use probes which are inserted into each individual radiating element of the array antenna. For 6-bit phase shifters, this method is not suficiently accurate. A method and an apparatus are disclosed wherein the aperture illumination of the array antenna is determined from the output of an integral waveguide and compared with a desired aperture illumination. The difference between actual value and desired value is compensated for iteratively with the aid of an adaptive control system.

Abstract: A peristaltic pump, which includes a flexible tube arranged along a circular path and in which a compression member is driven by an electric motor via a gearing, is to be compact and easy to manufacture, so that it can be produced at such a low cost as to be also suitable for applications where it has previously been too expensive. To accomplish this, parts of the pump are combined with parts of the gearing.

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: A radiotelelphone system in the form of a private branch exchange (12) within and/or outside one or more buildings is equipped with a plurality of mobile subscriber units (28), a plurality of transmitter/receiver units (27) capable of communicating with the subscriber units (28) by radio, and a central unit (26) cooperating with the transmitter/receiver units (27). In order that such a radiotelephone system not only permits mobile telephoning within and/or outside buildings but also can be installed later and adapted to changing requirements in a simple manner, the transmitter/receiver units (27) are arranged and designed to form not only a radio link to at least one of the subscriber units (28) but also, via respective adjacent transmitter/receiver units (27), a radio-link chain (radio bus) to the central unit (26), which has a separate transmitter/receiver unit.

Abstract: Microwave landing systems are used to enable aircraft to make landings even in poor visibility. One distinguishes three categories of approach and landing manoeuvers. Of particular importance are Category III operations, i.e., those in which the pilot depends exclusively on the navigation system, because he cannot see the runway. Throughout a Category III landing operation, it must be ensured that the navigation system does not fail, and that the information contained in the signals being radiated by the navigation system is reliable. To that end, two executive monitors are arranged such that the first to detect a signal error functions as a master monitor. If the slave monitor then detects (within a reduced error threshold) the same signal error, an error in the system being monitored is confirmed and appropriate safety measures are taken (e.g. immediate changeover from the faulty transmitter).

Abstract: A test adapter is disclosed for connection to a measuring instrument using a 4-conductor measuring technique. It has four coaxial connectors whose characteristic impedance is adapted to that of the measuring instrument. The supply lines are designed as a stripline whose characteristic impedance is equal or approximately equal to that of the coaxial connectors.

Abstract: A circuit for filtering pulse sequences of a given frequency out of a composite signal includes a series combination of a monostable multivibrator (MF) and a random-access memory (RAM), an address register and a clock. The monostable multivibrator (MF) serves as a pulse shaper of incoming signals. The input (D.sub.E) and output (D.sub.A) of the random-access memory (RAM) are connected to the inputs of an AND gate (UG). An address counter register (AR) associated with the random-access memory (RAM) has a count cycle whose duration is equal to the pulse spacing of the sequence to be recognized. During each clock period (T2), the current signal state of the input (D.sub.E) of the random-access memory (RAM) and the content of the addressed memory cell are checked for equality by the AND gate (UG) and the current signal state is then written into the cell.

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: An impeller formed from sheet-metal by stamping and bending, at a low production cost, capable of delivering an increased quantity of air at a reduced noise level and with reduced power consumption and enhanced efficiency. The method of manufacturing the impeller from sheet metal incorporates sufficient versitility to allow the blades of the impeller to be formed to any desired configuration in order to provide an optimum shape for the intended impeller use. The blades can be curved or twisted and can extend perpendicular from the sheet-metal surface or at any desired angle for optimum utilization.