Abstract: A method for mimicking a stream of self-similar traffic in a telecommunications network in which a continuous-time Poisson arrival process is applied to an M/G/∞ system, such that the continuous-time Poisson arrivals have a predetermined mean arrival rate and a predetermined service time distribution. A stream of self-similar traffic is generated based on the count process of the arrivals formed in the M/G/∞ system, such that the self-similar traffic has a selected mean arrival rate and a selected autocorrelation function. The generated stream of self-similar traffic is applied to a portion of a telecommunications network and a behavior of the portion of the telecommunications network is then simulated based on the applied stream of self-similar traffic.

Abstract: At a transmission line (La', Lb') connected with telephone station equipment (Tel) via a lowpass filter (TP), via which telephone station signals are transmitted in a first frequency range, there is connected via a line transformer (U3) a data terminal (DG) which is able to receive and to send data signals in a second frequency range above the first frequency range. On its side toward the transmission line (La', Lb'), the lowpass filter (TP) has a capacitive termination (C7) which is rated so that its a-c resistance is in the order of magnitude of or preferably less than the characteristic impedance of the data transmission line in the second frequency range.

Abstract: A miniature hydrophone is disclosed which contains a piezoelectric foil as a base element (2) with a linear arrangement of multiplicity of detector elements (10). In accordance with the invention, the electrodes (5) are arranged on a top surface (15) of one of the flat sides of a support (16) and are capacitively coupled by a bonding layer (6) to the base element (2). The detector elements (10) are associated with an amplifier (32) which, with equal length connecting leads (11, 26 and/or 12, 27), is fastened to a side face of the support (16). The electrical interconnection between the detector element (10) and the associated amplifier (32) employs a groove (24) through the corners of support 16. Additional such modules can form an assembly unit in a row arrangement of a size equal to that of the detector elements (10).

Abstract: A concentrator equipped with two processors is connected via two corresponding channel systems to a higher ranking exchange. Both processors operate independently of each other and poll all subscriber line circuits for switching codes. In the event that a channel system malfunctions, but the concentrator processor is operational, one processor transmits request signals, as well as an emergency operating state signal, to the subscriber line circuits. If the processor itself malfunctions, it transmits request signals and, in addition, an out-of-order state signal. The emergency operating signal and out-of-order signal are stored by each of the subscriber line circuits. Switching codes are transmitted to each of the two processors when both of these processors are in standard operating mode or in emergency mode.

Abstract: A circuit arrangement for suppressing interference signals on the receiving arm of a subscriber line circuit is constructed from electronic components and thus comprises no speech transformers. The receiving arm of the subscriber line circuit (SLIC) is connected to a two-pole filter circuit (ZF) which consists of the parallel arrangement of a parallel--and a series--resonance circuit (LP,CP and LS,CS), the resonance frequency of which corresponds to the frequency of the signals which are fed-in for the transmission of charge pulses and which charge pulses can manifest themselves as interference signals when reflected without the provision of the described measures.

Abstract: A voice switched gain system is disclosed for loudspeaking telephone and hearing aid applications involving electret microphones. A voice switched gain circuit comprises an audio pre-conditioning circuit for providing a conditioned audio input referenced to an unconditioned audio input to a compandor circuit. A linear gain level reference generator circuit generates a level for comparison with the audio input level. A decision circuit then controls the compandor operation based on the result of the comparison. The decision circuit either maintains the audio output of the compandor in a compressed state or expands the audio input signal to a higher level expanded state for transmission. Two such circuits are provided in a loudspeaking telephone system, one circuit for maintaining a preemptive near end control through appropriate timing of the dual decision process. Far end control is provided by the other voice switched gain circuit.

Abstract: In each case, a common interface module is assigned to subscriber lines and/or trunk groups. This interface module is connected both to the speech path switching network and, via a data transmission trunk group, to a central controller which establishes the switching paths. The information is transmitted via the speech path switching network using pulse code modulation. To provide central control for the telephone exchange, the information is transmitted via a data transmission trunk group using a message format with variable data length (HDLC procedure). Each interface module is assigned an interface circuit for transmitting information to and receiving information from the connected subscriber lines and/or trunk lines, for buffering speech and signal information, and for monitoring status. Speech and signal information are transmitted based upon the control commands of the central controller and based upon a peripheral controller assigned to the interface module.

Abstract: Analog voltages are collected by scanning the two wires of a subscriber line; the values are subjected to an analog-digital conversion and fed to a microprocessor (MC) which computes the desired measuring values from the results of said conversion. Thus, from a single measuring operation performed at two measuring points, nine different voltage values can thus be obtained including dc, ac and external voltages between each wire and ground and between the two wires.

Abstract: A transformerless hybrid circuit arrangement for a subscriber line interface circuit of a telecommunications exchange is disclosed. A preferred embodiment of the hybrid arrangement comprises a first and a second operational amplifier plus a differential amplifier connected together in the following manner: The non-inverting input of the first operational amplifier is connected to a first reference voltage and the output of this amplifier is connected (1) via a first resistor to one wire of the two-wire subscriber line, and (2) via a third resistor to the inverting input of the amplifier. The non-inverting input of the second operational amplifier is connected to a second reference voltage and to the receiving branch of the four-wire line of the telecommunications exchange.

Abstract: Method and apparatus for the correction of image distortion in the digital transmission of video signals, in which at the receiving end a comparison is made between the received signal values and estimated video signal values computed from adjacent video signal values. When a prescribed threshold value is exceeded by the amount of the difference between the video signal value and the associated estimated video signal value, the corresponding estimated video signal value is forwarded instead of the received video signal value. A feature of the present method and apparatus is their ability to distinguish edges of objects when there are sharp fluctuations in expected signal level values.

Abstract: In a small PABX with a switching matrix that has electronic crosspoints, integrated selector components comprising multiplexers or demultiplexers in C-MOS technology are used for the switching matrix. By means of individual dialing connection points, which are determined by an appropriate control address supplied by a control computer unit, the individual subscriber lines are to be connected together in internal traffic, and the subscriber lines are to be connected with an exchange line in external traffic. The switching matrix is electrically separated from other operating units by repeating coils in the subscriber lines and in the exchange lines. Central units (tone receiver, tone generator) are connected through free dialing connection points of the multiplexers.

Abstract: An ultrasonic transducer system is disclosed consisting of a support body (2), a radiating layer (8,9), a first .lambda./4 matching layer (10,11) and a second .lambda./4 matching layer (12,13). According to the invention, at least two ultrasonic transducers (4,6) with different and predetermined mid-frequencies are attached to a common support body (2) and have natural foci which overlap if the ultrasonic transducers (4,6) are mechanically separated. The ultrasonic transducer (4), having the higher mid-frequency, is provided with a larger radiating surface (4). This configuration, through the appropriate selection of the mid-frequencies, allows compensation for the frequency dependent damping of the transmission medium by frequency related weighting during radiation. In this manner, substantial improvements with respect to bandwidth of the total transmission path, from transmitting transducer through transmission media to receiving transducer, and the image quality can be realized.

Abstract: A circuit for generating a gate bias for field effect transistors in which one or several field effect transistor(s), identical within certain tolerances are paralleled and have a channel current above a predetermined value, is (are) connected to one or more electrically operated light sources so that at least a part of the channel current operates the light sources which radiate light. The light is received in a photocell and is converted to a dc voltage fed directly or indirectly to the gate(s) of the field effect transistor(s) in such a manner that the gate voltage thus supplied counteracts the channel current, and that an electrical device for the adjustment of the channel current is provided. The device described is especially well suited for application in microwave technology.

Abstract: A casing for electrical components, component assemblies or integrated circuits, and particularly for electrical surface-wave filters, is disclosed as well as a method of production therefor where the electrically active element rests on a base strip from which project outgoing connectors through the casing walls. The connectors provide mechanical and electrical connection to printed circuit boards. A thermosetting-plastic trough adheres closely to the underside of the base strip, while the side-wall reels of the trough rest on the borders of the upper surface of the base strip. Over the trough is placed a thermosetting-plastic lid so that the active element is contained in an enclosure. The trough-and-lid assembly is then coatable in thermosetting plastic.

Abstract: Amplitude-modulated carrier frequency oscillations are supplied to the demodulator of the present invention whose peak value is maintained constant on its receiving side by a controller. The carrier frequency oscillations are supplied via a capacitor to the two inputs of a NOR gate. Both inputs of the NOR gate are connected via a resistor with the output thereof. The output of the NOR gate is connected with an inverter, at whose output the evaluated carrier frequency oscillations in the form of data are collected. Because the different elements of C-MOS circuits inherently exhibit different threshold values, the comparator functions required for demodulation can be realized at little expense using the gates of a C-MOS circuit.

Abstract: To record the address of a storage cell that has contents that are erroneous with respect to the coding, a memory configuration, connected by means of a bus line system with a central control unit, is equipped with a register in the recording cells of which can be written the address of the selected storage cell which is transmitted over the bus line system during the performance of a read cycle in the memory's configuration. Each memory contents that are read out from one of the storage cells in the course of such a read cycle are checked in an error-recognition circuit for the existence of a coding error. When a coding error of this kind is recognized, the error recognition circuit then emits an appropriate error signal. In response to such an error signal, a control device locks out the register for the reception of another address transmitted over the bus line system.

Abstract: A central control unit that is connected with a number of circuit assemblies and has two interrupt inputs. Of these interrupt inputs, at first, when the circuit assemblies are in a fault-free state, only the one with the lower interrupt priority is activated. A register is provided, into which, when the circuit assemblies are driven by the central control unit, data with regard to the precise circuit assembly that is being driven in each case can be written. In addition, there is provided at least one fault recognition circuit, which when a fault exists in the respective circuit assembly, emits a fault signal when that assembly is driven. Connected with the abovementioned interrupt inputs is a control device, which, in response to such a fault signal, effects, through the activated interrupt input, the performance of a first interrupt routine, in the course of which the interrupt input with the higher interrupt priority is activated.

Abstract: In order to be able to regulate in a simple and reliable manner the quantity of liquid that is administered to a patient through a hose in an infusion device, there is provided, according to the invention, a motor-driven eccentric, which presses the hose against a blocking device and clamps it off to a greater or lesser degree. The blocking device forms a part of at least one guide for the hose and can assume two positions. In one of the positions the guide is released; in the other position it is closed. A lever mounted with freedom to rotate, which can be spring-loaded, is particularly well suited for the blocking device. In addition, a clamping lever which can be activated through an electromagnetic latch, can be provided as an emergency stop.

Abstract: The invention relates to a transmission testing arrangement for executing performance tests for a telecommunication system which includes a central switch to the common control unit, a switching network, and line interface units internally connected to the switching network and adapted for connection to a corresponding line circuit. The testing arrangement includes a bus-oriented microprocessor system for synthesizing and analyzing test signals, a program memory, a main memory, and first and second interface modules.

Abstract: In order to control the transmission capacity of the receiving branch of a transmission system comprising this receiving branch as well as a transmitting branch with an echo compensation network, the system generates a level-indicating signal, which indicates, at an output of an amplifier (Am), the signal level contained in the receiving branch, plus a level change-indicating signal, which indicates level changes in this branch. These two signals are linked logically to one another in such manner that the output circuit of the amplifier (Am) is enabled for signal transmission only upon simultaneous occurrence of a level-indicating signal which indicates the presence of a prescribed level and a level change-indicating signal which indicates that a prescribed level change has not been exceeded.