Abstract: In order to reduce mutual interferences between POLMUX and signals, the signals are transmitted with differed to each other carrying signals, thereby making it possible to obtain the circular polarization of each resulting POLMUX signal. Each second POLMUX signal is transmissible with an opposite circular polarization. In order to reduce also interferences when only one modulated data signal is transmitted through a POLMUX channel, a polarization plane of modulated data signals of each second POLMUX channel is turned at 45°. In a variant, polarization multiplex signals are produces and the resulting polarizations thereof in adjacent channels are perpendicular to each other.

Abstract: In the signal quality detector (7, 8, 10), a 3R-regenerated electrical received signal (REDS) is correlated with a non-regenerated received signal (EDS). The result is a direct measure of the correlation between non-regenerated and regenerated received signals and can be used for controlling a PMD-compensator (3).

Abstract: Method for reducing signal degradation in an optical polarisation-multiplex system. The modulated optical signals to be transmitted are synchronised or generated such that the phase difference for NRZ-modulated signals is at least approximately 0° and the phase difference for RZ-modulated signals is at least approximately 180°. They can also be achieved by means of different synchronising devices.

Abstract: In order to reduce mutual interferences between POLMUX and signals, the signals are transmitted with differed to each other carrying signals, thereby making it possible to obtain the circular polarization of each resulting POLMUX signal. Each second POLMUX signal is transmissible with an opposite circular polarization. In order to reduce also interferences when only one modulated data signal is transmitted through a POLMUX channel, a polarization plane of modulated data signals of each second POLMUX channel is turned at 45°. In a variant, polarization multiplex signals are produces and the resulting polarizations thereof in adjacent channels are perpendicular to each other.

Abstract: Method for reducing signal degradation in an optical polarisation-multiplex system. The modulated optical signals to be transmitted are synchronised or generated such that the phase difference for NRZ-modulated signals is at least approximately 0° and the phase difference for RZ-modulated signals is at least approximately 180°. They can also be achieved by means of different synchronising devices.

Abstract: The stimulated Brillouin backscatter is reduced by non-linear effects, such as self-phase modulation or cross-phase modulation. Due to the cross-phase modulation, a bandwidth spread and, as result thereof, a reduction of the stimulated Brillouin backscatter is also achieved by supplying at least one amplitude-modulated pump signal.

Abstract: A circuit arrangement is disclosed for the correction of step distortions in a transmission of data employing frequency-modulated data signals. The circuit arrangement contains a demodulator which compares time durations between edges of the frequency-modulated data signals with a measuring time duration generated in a timing element and generates demodulated data signals after an integration. The demodulated data signals are compared in a comparator to reference signals and the signals at the output of the comparator are integrated in an integration element. The integration element emits control signals to the timing element. With these control signals the measuring time duration is changed in such manner that the step distortions of the demodulated data signals are opposed.

Abstract: A circuit arrangement is described for carrying out a diversity selection from a number of data channels. The diversity channels are connected to a majority logic decision stage. The diversity channels and the output from the majority logic stage are connected to a channel switch as data channels. By means of a quality evaluation stage, one of the diversity channels is switched through to the data bank under the control of signals produced responsive to an indication that a minority of the diversity channels is better than each of the remaining diversity channels by a given quality difference. The majority decision channel is switched through with one of the control signals when the majority of the diversity channels are poorer than the remaining diversity channels during the given test period by another given quality difference.

Abstract: A circuit arrangement for data transmission systems is described wherein the transmission of excessively faulty data signals is recognized and prevented, thereby stopping the transmission of senseless text. A fault discriminator emits a fault signal which is subsequently integrated. The integrated fault signal, if it exceeds a predetermined value, triggers a threshold value stage to produce a blocking signal. The blocking signal acts on the circuitry in a data sink, e.g., a teleprinter, to suppress the processing of the received data.