摘要:
The invention relates to improvements in or relating to modulation in an Optical Network, and to an apparatus, a method and a communications network for modulation in an Optical Network. An apparatus is arranged to receive a modulated optical signal comprising a carrier wavelength and first data. The apparatus is arranged to substantially erase the first data from the optical signal by performing an inversion operation on the modulated optical signal. The apparatus is arranged to receive second data and to modulate the carrier wavelength with the second data for onward transmission of the second data. The inversion operation comprises applying a signal comprising an inverse of the first data to at least a portion of the modulated optical signal. The signal may further comprise the second data such that the modulation of the carrier wavelength and erasure of the first data is performed in a single operation.
摘要:
The present invention relates to an individualized self-monitoring system for transformers (31, 33) in a electric power measurement installation that comprises at least a transformer (31, 33) and at least a time-integrated electrical quantity meter (3, 4, 13), directly coupled to one of the windings of the transformer (31, 33), the meter (3, 4, 13) being capable of measuring and recording the electrical quantity of said winding.The present invention also relates to a method of monitoring and diagnosising transformers (31, 33) in a power measurement installation that comprises the steps of measuring the values of at least a directly measured time-integrated electrical in at least a winding of at least one transformer (31, 33), performing comparisons between the measured and generating diagnostic results with the compared data.
摘要:
An optical network terminal (ONT) for use in an optical access network and comprising: an optical transceiver arranged to communicate with an optical line terminal using a wavelength which is modulated to carry sub-channels; a second transceiver arranged to communicate with a number of subscriber equipment using respective subscriber equipment channels; the ONT arranged to automatically map each subscriber equipment channel to a respective sub-channel of the wavelength without using an address associated with the respective subscriber equipment.
摘要:
The invention relates to improvements in or relating to optical networks. Methods and apparatus are disclosed for providing communications services to at least one user. Transmission of an optical signal in the downstream direction is described comprising at least one Wavelength Division Multiplexing channel such that at least one of the channels is an unmodulated channel. The unmodulated channel is arranged to transmit user data from the at least one user in the upstream direction.
摘要:
A method and apparatus for compensating for channel depletion of a multi-channel signal in an optical link or optical network comprising a chain of optical amplifiers. The method comprises determining channel depletion for each amplifier from the power of the input signal to the optical amplifier and the power of the output signal from the previous amplifier. Each amplifier is then controlled to amplify the signal to a level equal to the nominal (ideal) power plus the calculated channel depletion for that amplifier.
摘要:
A method of assessing the feasibility of a composite optical path in an optical communications network in which the composite path is composed of two optical paths k1 and k2 is described. The method comprising the steps of: defining, for each individual optical path k and with type i interface, at least one parameter indicating its feasibility, calculating a quality Q factor Q′_i,k1+k2 of the signal for the composite path, estimated considering the deterioration which affects transmission over the paths k1 and k2 and comparing this quality Q′_i,k1+k2 with a value Qbare_i which is defined as the lowest value which can be taken on by a mapping function Q_i(.) for interface i and which gives the Q factor as a function of the OSNR received evaluated under the conditions that are considered to be the worst case that can be accepted whilst ensuring the desired signal quality and wherein the composite connection is considered feasible if Q′_i,k1+k2>=Qbare_i.