Abstract: Prior art methods used for monitoring, via monitoring means, signals which are to be transmitted via telecommunication links and with said signals each comprising a signalling signal and a content signal, require that the processing means which are required for monitoring are either situated in the vicinity of the monitoring means or must be coupled to the monitoring means via leased-lines. By having the monitoring means generate a further signalling signal, dependent upon a code word related to a signalling signal, and consequently transmitting, dependent upon the further signalling signal, a content signal which is to be monitored to the processing means, a substantial more efficient method is obtained as both means can be coupled via a public telephony network.

Abstract: A polarisation-independent optical device for influencing the phase of an optical signal includes, in a light conductor (11), two identical adjustable phase shifters (14, 15), between which there is placed a polarisation converter (16). Optical signal components (I) entering at the input (12) of the light conductor as TE and TM polarisation modes, leave the light conductor at an output (13) as TM and TE polarisation modes having the same phase differences with respect to the signal components at the input. By way of simultaneous control of the phase shifters (14, 15) having a same modulation voltage V, there is obtained a polarisation-independent phase modulator. By including such a phase modulator in a branch of an MZ interferometer and placing, in the other branch, an identical polarisation converter, there may be realised a polarisation-independent switch or an intensity modulator.

Abstract: Integrated optical mode converter provided with a channel-shaped waveguide comprising a periodic concatenation of two wave-guiding subsections (P) and (Q) defined by a strip-shaped structure supported by a substrate. The waveguide profiles of the subsections (P) and (Q) are defined by two different partial strips, of which at least one is, but preferably both are, provided with a slot (S.sub.P, S.sub.Q) running in a longitudinal direction of the partial strip in question. The slots have been applied in such a manner that only the field distribution of one of the two guided modes involved in the mode conversion is affected. The resulting structure has increased conversion per interface; and lower attenuation in specific embodiments.

Abstract: An integrated optical polarisation splitter comprises a first waveguiding section (A) with a first guide (21), a second waveguiding section (C) with a second and a third optically decoupled and physically separated guides (24, and 25 or 28) and an intermediary section (B) for a coupling between the first and the second section. The intermediary section (B) comprises a first monomodal waveguide (22) and a second bimodal waveguide (23), which are optically coupled over a length L. The bimodal waveguide (23) has a propagation constant for the first-order guided mode of one polarisation (TE or TM), which is equal to the propagation constant for the zero-order guided mode of said polarisation (TE or TM) of the monomodal waveguide (22). The two coupled waveguides have different propagation constants for the remaining guided modes.

Abstract: A method of calculating the transmission quality of a series of cascaded codecs, wherein for each type of codec, a function is determined which is specific for the relationship between the Q-equivalent over a series of codecs of that same type and the number of codecs which said series includes. The type sequence is determined of the series of codecs such as those cascaded in the transmission medium. The series is traversed in steps and, starting from the Q-equivalent for one codec of the type which occurs as the first in the series of codecs, the Q-equivalent is always calculated over the traversed part of the series by calculating, starting from the Q-equivalent calculated last, the next Q-equivalent under the control of the function which is specific for the type of the last codec in said part which has been traversed. The Q-equivalent finally calculated for the entire codec series is converted into a MOS value which is a measure of the subjective quality of the codec series.

Abstract: Known processor systems comprising a processor and memory fields for containing computer interface profiles each having a number of elements each representing a function are static systems. The processor system according to the invention is a dynamic system, by allocating an element parameter to an element, which element parameter is a function of the number of times this element has been activated, for example per time interval, and by comparing this element parameter with a predefined value. In dependence of the comparison result, the element is displayed directly or indirectly.

Abstract: A sampled analog signal is filtered by a short-term prediction filter. The result, a segmented residual signal, is transformed from a time domain to a frequency domain into several frequency components, each having a frequency-component amplitude. If a number of new amplitudes is calculated by combining the several frequency-component amplitudes, such that the number of new amplitudes is smaller than the several frequency-component amplitudes, a more efficient coder is created. The reduction of the quality of speech coding, due to loss of information, could be decreased if this calculation is based on the so-called Bark scale (critical frequency bands). In a corresponding speech decoder, at the hand of the number of new amplitudes several new frequency-component amplitude are calculated (the number of new amplitudes being smaller than the several new frequency-component amplitudes), which then are inverse transformed from a frequency domain to a time domain into new subsegments.

Abstract: In a transmission system for the transmission of data cells between local stations and a central station, cell arrivals are registered in a local register (CAR). Those registrations are periodically transmitted to the central station. The central station thereafter transmits the permit codes to the various local stations, in order to transmit the data cells which are most ready. In each local station the data cell which is most ready for transmission is transferred from a cell arrival buffer (CAB) to a cell departure buffer (CDB) as long as the permit code expected for the station, on the basis of the number of time slots since the cell arrival, remains forthcoming. The data cell remains in the buffer as long as no permit code addressed to the station is received. The data cell is transmitted as yet after the reception of a permit code addressed to the station. The data cell is discarded, however, as soon as an empty (unaddressed) permit code is received while the data cell still resides in the buffer.

Abstract: For removing coating material from an end (5) of a fiber ribbon (1) over a length L, while using a chemical softening agent, the end is received and clamped between clamping parts (9, 35) of a holder. The clamping parts form a casing wall of a space in which the fiber ribbon with the end extends inwardly over said length L. Softening agent is supplied into the space via a supply opening (47), and brought into contact with coating material of the end, preferably via a layer of material (49) soakable for the softening agent. Adjacent to the point where the end extends inwardly through the wall formed by the clamping parts, scoring knives (33, 43) are mounted for scoring the coating material. One of the clamping parts is provided with an exhaust opening (51) for exhausting surplus softening agent. After softening the fiber ribbon (1) is withdrawn, with the end clamped, from holder (9).

Abstract: An optical wavelength demultiplexer comprises a monomodal incoming waveguide (1) for an incoming optical signal (S(.lambda..sub.1, .lambda..sub.2, .lambda..sub.3, .lambda..sub.4)) being propagated in fundamental guided modes having different polarisations (TE and TM), a conversion device (22) for converting the fundamental modes of one of the polarisations in first-order modes of the other polarisation, a divergence area (23) in which after conversion the incoming signal enters and diverges, a phased array (3) of curved monomodal waveguides provided with an entrance plane (7) and an exit plane (S), for receiving and further guiding the diverging optical signals, a convergence area (32) in which optical signals exiting at the exit plane (8) converge into signal beams (S(.lambda..sub.i)) converging into separate wavelength-dependent focuses (F.sub.i), and exiting bimodal waveguides (33(i)) joining to said focuses (Fi), thereby providing polarisation independent operation.

Abstract: A coupling device for coupling a videotelephone with a video generation device. The coupling device includes (i) a first device, for detecting at least one code word contained in a signal originating from the videotelephone, (ii) a second device, coupled with the first device, for generating a control signal in response to the detected code word, and (iii) a change-over device. The change-over device is coupled with the first device and with the second device. The change-over device receives, from the video generating device, both a first video signal, coded in a first manner, and a second video signal, coded in a second manner. The change-over device then feeds, in response to a control signal, coded video signals originating from one of a number of video generating devices to the first device via the change-over device. The coupling device is readily applicable in multicast environments.

Abstract: The invention relates to a method for checking data sequences, comprising a protection step and a verification step, with a control sequence being formed in the protection step on the basis of an identification sequence, which identification sequence comprises identification values which identify data sequences which are to be protected, and which control sequence comprises control values of which at least some have been formed on the basis of operation values, which operation values have been derived from data of sequences which were identified by the said identification values, and with the data sequences being verified, in the verification step, on the basis of the control values. In accordance with the invention control values are formed, successively, by combining an identification value with an operation value related to a preceding control value. The invention is especially useful for verifying data files.

Abstract: A method for installing a tubular cable-duct around a cable buried in the ground includes steps of freeing a portion of the buried cable from the ground in a forward longitudinal direction of the cable, starting from a free end of the buried cable, and advancing a foremost end of the cable-duct and subsequent portions of the cable-duct in the forward longitudinal direction of the cable over the portion of the cable freed from ground, starting from the free end of the cable. The advancing step includes the sub-steps of exerting pulling forces on the cable with a pulling device engaging the free end of the buried cable in a direction which is substantially opposed to the forward longitudinal direction of the cable, and exerting pushing forces with a pushing device engaging the cable-duct in a direction which is substantially opposed to the direction in which the pulling forces are exerted.

Abstract: Improved integrity of a payment system for paying for services or goods, for example, telephone facilities, through use of electronic payment cards. In any session to increase a card balance, a "flag" is placed ("1") on the payment card which indicates that the session must not be interrupted. After completion, the flag is removed again ("0"). A session to pay for the product or the service or to increase the balance can only be established if the flag is absent ("0") indicating that the last session to increase the balance was correctly completed. If, on the other hand, the flag is still "1" at the start of a session, a correction routine is first performed in which the previous session to increase the balance is then correctly concluded to prevent the flag being removed by fraud, the flag can only be removed by a central system (PSTN/ABS) through issurance of an authorized instruction.

Abstract: The invention relates to a communication system comprising a first network, a second network, first stations coupled to the first network and second stations coupled to the second network, with the first network and the second network being mutually coupled. The system comprises queuing means for recognizing calls for a group of second stations and for placing said calls in a queue, and control means for assigning to calls in a queue a connection to a second station. In accordance with the invention in such a communication system the queuing means are coupled to the first network, so that the queuing means are not formed in the second network. The first and the second network can be national telephone networks of different countries.

Abstract: Method for the polling of queues. A ratio table is derived from, for example, the numbers of elements in the queues at any one moment. The sum S is calculated of the ratio values R(x) to the various queues. Next, a correction factor C(x) is assigned to each queue, which correction factor is equal to S, decreased by the ratio value of that queue. Further an urgency factor U(x) is assigned to each queue. The queue to be polled next is, in each case, the queue with the highest value of U(x) or, for example where values of U(x) are equal, the first occurring queue with that value. Thereafter the urgency factor U(x) of the selected queue is reduced by the value of its correction factor C(x), whilst the urgency factor U(x) of the remaining queues is increased by their ratio value. The queue to be polled next is then again the queue with the highest value of U(x), and so forth. The method is pre-eminently applicable for ATM, eg. for the polling of subscriber terminals in a passive optical network.

Abstract: Known systems based on stereoscopic video coding and video decoding code with inadequate efficiency because the left-hand picture and the right-hand picture are coded and decoded independently of one another by means of the encoders present in the system. As a result of providing one encoder with switching means to which a signal representing the left-hand picture and a signal representing the right-hand picture are fed, said encoder is able to base the prediction either on the left-hand picture or the right-hand picture, and this improves the prediction and, consequently, the efficiency of the coding.

Abstract: In a speech coder, a sampled analog signal is filtered by a short-term prediction filter. The result, a segmented residual signal, is transformed from a time domain to a frequency domain into several frequency components, each having a frequency-component amplitude. If a number of new amplitudes is calculated by combining the several frequency-component amplitudes, such that the number of new amplitudes is smaller than the several frequency-component amplitudes, a more efficient coder is created. The reduction of the quality of speech coding, due to loss of information, could be decreased if this calculation is based on the so-called Bark scale (critical frequency bands). In a corresponding speech decoder, at the hand of the number of new amplitudes several new frequency-component amplitude are calculated (the number of new amplitudes being smaller than the several new frequency-component amplitudes), which then are inverse transformed from a frequency domain to a time domain into new subsegments.