Abstract: The invention relates to a method for maintaining the compatibility of legacy receivers in network termination units of an optical distributing network structure, especially in a passive optical network, when in the distributing network structure advanced receivers with a multiple of the data rate of the legacy receivers shall be operated too, in which signals for the advanced receivers are transmitted on the same wavelength and using the same physical paths as signals for the legacy receivers, in which, while transmitting signals for the advanced receivers at the same time also signals for the legacy receivers are transmitted, and in which the amplitude of the signals for the advanced receivers compared to the amplitude of the signals for the legacy receivers are chosen such that the signals for the advanced receivers do not block the legacy receivers in the receipt of the signals intended for them.

Abstract: Stationary interference signals from radio stations, for example, enter a transmission network (NET), e.g., a coaxial cable network with return channel, and impair the transmission of broadband signals, e.g., data, in the upstream frequency band, since they lie in the same frequency range. The transmitting/receiving unit (SE1) of a terminal (END) contains a receiving unit (EMP1) for receiving frequency values of stationary interference signals induced in the transmission link, a memory (MEMO1) for storing the received frequency values, a generator (SG1, NG1) for generating a spreading function with spectral zeros at frequency values which are determined from the stored frequency values, and a multiplier (MUL1) for multiplying the broadband signals to be transmitted by the generated spreading function with spectral zeros.

Abstract: In a hybrid fiber/coax access network (NET) with downstream and upstream channels, the upstream channel serves to transmit voice and video signals as well as data signals from groups of customer locations (END) to a subcenter (HUB). A demarcation point (UP) provides the interface between the access network (NET) and the private network of the customer location (END). It contains at least two devices (BP4, BP5, BP6) for frequency-splitting received signals in the upstream frequency band, at least two switches (S4, S5, S6) following the at least two devices (BP4, BP5, BP6) and serving to block or unblock individual upstream frequency ranges, a measuring unit (MESS2) for measuring the amplitudes or intensities of the signals in the split frequency ranges, and a control unit (CTRL) for evaluating the measured values and controlling the at least two switches (S4, S5, S6). For a customer location (END), individual upstream frequency ranges can thus be telemetrically blocked for a limited time.

Abstract: Stationary interference signals from radio stations, for example, enter a transmission network (NET), e.g., a coaxial cable network with return channel, and impair the transmission of broadband signals, e.g., data, in the upstream frequency band, since they lie in the same frequency range. The tranmitting/receiving unit (SE1) of a terminal (END) contains a receiving unit (EMP1) for receiving frequency values of stationary interference signals induced in the transmission link, a memory (MEMO1) for storing the received frequency values, a generator (SG1, NG1) for generating a spreading function with spectral zeros at frequency values which are determined from the stored frequency values, and a multiplier (MUL1) for multiplying the broadband signals to be transmitted by the generated spreading function with spectral zeros.

Abstract: In a hybrid fiber/coax access network (NET) with a forward channel and a return channel, the return channel serves to transmit voice and video signals as well as data signals from groups of terminals (NT1; NT2) to a subcenter (HUB). Access by a group of terminals (NT1; NT2) to a shared electric line (KOAX1; KOAX2) is obtained by TDMA, FDMA, or CDMA, for example. An optical network termination unit (ONU) is connected to one or more electric lines (KOAX1; KOAX2). For each line or for each separate frequency range of the return channel, the optical network termination unit (ONU) contains an analog-to-digital converter (A/D1, A/D2) which digitizes the received signal. If two or more analog-to-digital converters (A/D1, A/D2) are provided, the individual digitized signals are multiplexed in a multiplexer (MUX) and then fed to a digital electrical-to-optical transducer (E/O2).

Abstract: In a hybrid fiber/coax access network (NET) with a forward channel and a return channel, the return channel serves to transmit voice and video signals as well as data signals from groups of terminals (NT1; NT2) to a subcenter (HUB). Access by a group of terminals (NT1; NT2) to a shared electric line (KOAX1; KOAX2) is obtained by TDMA, FDMA, or CDMA, for example. An optical network termination unit (ONU) is connected to one or more electric lines (KOAX1; KOAX2). For each line or for each separate frequency range of the return channel, the optical network termination unit (ONU) contains an analog-to-digital converter (A/D1, A/D2) which digitizes the received signal. If two or more analog-to-digital converters (A/D1, A/D2) are provided, the individual digitized signals are multiplexed in a multiplexer (MUX) and then fed to a digital electrical-to-optical transducer (E/O2).

Abstract: An electrical transmission system is indicated, in which a broadband distribution network (2) has a center (1) and a number of terminals (26) connected thereto, which can receive TV and Audio signals emitted by the center (1), and individual subscriber signals, and which can send upstream signals to the center (1). The broadband distribution network (2) has a number of amplifiers (10) that are close to the subscribers, to which a group of terminals (26) is connected, each of which is connected to a back-channel facility (4). The back-channel facility (4) is connected to a two-wire line (21) which is indirectly connected to the center (1). The back-channel facility (4) evaluates the upstream signals sent by a group of terminals (26).

Abstract: Stationary interference signals from radio stations, for example, enter a transmission network (NET), e.g., a coaxial cable network with return channel, and impair the transmission of broadband signals, e.g., data, in the upstream frequency band, since they lie in the same frequency range. The transmitting/receiving unit (SE1) of a terminal (END) contains a receiving unit (EMP1) for receiving frequency values of stationary interference signals induced in the transmission link, a memory (MEMO1) for storing the received frequency values, a generator (SG1, NG1) for generating a spreading function with spectral zeros at frequency values which are determined from the stored frequency values, and a multiplier (MUL1) for multiplying the broadband signals to be transmitted by the generated spreading function with spectral zeros.

Abstract: A transmission system with a number of tap devices (1), which are connected to a distribution network (9). Subscriber terminals (11) can be connected to each tap device (1) present in a building (10), by means of a private, in-house network (13); these terminals can send upstream signals (AUF) to a center (8). A tap device (1) has first means (4, 5, 6) which attenuate an upstream signal (AUF) supplied to a second port (3) with a specified attenuation factor (a) and send it to the first port (2). The upstream signal (AUF) is sent out by a subscriber terminal (11) with a signal level which is selected so that after the attenuation, the upstream signal (AUF) has a level specified in the distribution network (9).

Abstract: In known optical distribution systems, a signal intended for the subscribers is distributed from a transmitting point to all network terminations (point-to-multipoint transmission). The receivers, which are connected to a passive optical network, are adapted to a common bit rate. If a need for a higher data rate arises at a network termination, this need can only be satisfied in the prior art by converting all receivers. This is not possible without interrupting the service. Furthermore, the conversion entails great expense, since the receivers of these network terminations where the need for information is unchanged have to be converted as well. By a time-division-multiplexing method, a time-division multiplex signal is generated which has a frame whose duration is equal to one bit period (T) of a digital signal, and which is divided into k time slots (ZS). At least two time slots (ZS) are used for one digital signal, and one respective time slot (ZS) is used for each of the remaining digital signals.

Abstract: A laser (2) of an optical transmitter (1) for the transmission of an analog broadband signal for CATV in particular, can be amplitude-modulated in two different manners with an intelligence signal (N). Direct modulation can lead to an undesired additional frequency modulation. With indirect modulation by means of an optical intensity modulator (3), Brillouin scattering occurs at powers of approximately 10 mW in an optical fiber of the transmission path connected to the optical transmitter (1). Both modulations lead to distortions of the transmitted signal. In order to avoid the disadvantages of both modulations in a technically simple fashion, the carrier emitted from a laser (2) is indirectly modulated with an intelligence signal (N) and the laser (2) also faintly directly modulated with an energy-dispersing signal (V).

Abstract: It is desirable to offer the subscribers of a cable television distribution network, in addition to the cable TV service, a video-on-demand service. Since, in the foreseeable future, the fiber-optic portion of the cable television distribution networks will not extend to the subscribers (111) but will terminate in optical network terminations (ONT.sub.i) from which a respective optical access network (108-110) will extend to the subscribers, the problem arises how to transmit the entirety of subscriber-assigned video signals to the subscribers so that the latter can receive the requested video signals. According to the invention, the transmission from the center (100) through the fiber-optic distribution network (101-107) to the optical network terminations (ONT.sub.i) is digital, using time- and wavelength-division multiplexing.

Abstract: An optical transmitter for the joint transmission of analog and digital signals is indicated, which, although it contains an optical transmitting component (5) with a laser, does not exhibit an increase in the bit error rate when transmitting the digital signals, due to so-called clipping. The clipping, a negative overmodulation of the laser to below the laser threshold, which occurs because of the constructive interference of the analog signal carders, is prevented by a limiter (8) located upstream of the modulation input of the optical transmitting component (5). The limiter contains a time-variant network that supplies a specified minimum voltage to the modulation input every time a comparator (7) determines that the modulation voltage has dropped below the predetermined threshold.

Abstract: In a fiber-optic amplifier, which consists of at least one pump coupler (2) with a pumping light source (1) and an erbium-doped fiber length (7) which is spliced to the pump coupler (2), at least one detector is located in the splice area (12) between the fiber length (7) and the outgoing transmission line, to monitor the amplifier by measuring the scattered light coming from this splice area (12). An electrical evaluating device follows the detector.

Abstract: To compensate for nonlinear signal distortions in analog optical communication transmission systems, caused by laser chirps and the chromatic dispersion of the optical fiber, an equalizer in the form of an LC component is known, whose capacitance is formed by a variable capacitance diode. However, the known equalizer functions only when the capacitance has the proper polarity, which cannot be predicted because of possible polarity inversion during signal transmission. According to the invention, the variable capacitance diode (C.sub.a) has another variable capacitance diode (C.sub.b), with the opposite polarity, connected in parallel, and is equally biased in the high-resistance direction. By adjusting the bias voltage of both capacitances, it can be achieved that one of the two variable capacitance diodes takes over the equalization function, and the other is practically inoperative.

Abstract: To compensate for nonlinear distortions in analog optical communication transmission systems, caused by laser chirps and the chromatic dispersion of the optical fiber, an equalizer in the form of an LC component is known, whose capacitance is formed by a variable capacitance diode. If this equalizer is to be adjusted for considerable signal distortions (long transmission path length), it must operate at great capacitance, which reduces its bandwidth. In order to be able to equalize large bandwidth signals (e.g. 600 MHz) containing considerable distortions, the invention indicates an LC chain circuit with LC components of the known type, as the equalizer. Further developments of this solution concern the appropriate polarizing of the variable capacitance diode and maintaining the frequency response constant, when adjusting the equalization.

Abstract: The invention is based on the problem of transmitting a frequency-division multiplex signal occupying a board frequency band, e.g., the cable television frequency band of 47-440 MHz, over an optical waveguide transmission section. According to the invention, in the transmitting unit, the whole frequency band to be transmitted is divided into two sub-bands (FB.sub.1, FB.sub.2), and the lower sub-band (FB.sub.1) is converted by means of single-sideband amplitude modulation of a high-frequency carrier (f.sub.0) into a higher-frequency transmission frequency band, e.g. 497-688 MHz, which is less than one octave in width, based on its lowest frequency. The lower sub-band (FB.sub.1) and the transmission frequency band produced by the conversion are converted separately into optical signals with different wavelengths (.lambda..sub.1, .lambda..sub.2) and are transmitted in a wavelength multiplex procedure via the optical waveguide.

Abstract: A method and apparatus for protecting a mixing apparatus for producing strand-shaped explosives and propellants in a twin-shaft screw extruder, the housing of which is formed of housing parts connected to a clamping device acting under hydraulic pressure. In order to compensate for excessive pressure and to prevent abrupt opening of the mixing chamber, the torque developed at the screw shafts is continuously monitered and fed to a control and storage device together with temperature and pressure values measured at the end of the screw shaft in the material being processed. If one of the measure values exceeds a permissable limit, a signal is produced to change the operating condition of the screw extruder, particularly to stop and withdraw the extruder from the housing, to halt the drive motor of the extruder shafts and to open the extruder housing by relieving the clamping device.

Abstract: A mixer having a mixing trough rotatable about a longitudinal axis with a charging and discharging opening and rotatable mixing and kneading blades within the trough is provided. A mixing shaft is connected to the blade and is driven by at least one hydraulic motor coupled directly to the mixing shaft. The motor is reversibly drivable by means of a displacement-controllable pressure pump. A driving clutch is provided between the mixing shaft and the mixing trough so that the mixing trough can be rotated and locked into different pivotal positions by an indexing fixing device.