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11. 发明专利

ES2010159T3 未知
公开(公告)号：ES2010159T3
公开(公告)日：1993-05-16
申请号：ES88203003
申请日：1988-12-23
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： BEKOOIJ, JOHAN PIETER
IPC分类号： H04B10/02 , C07K14/72 , H04B10/00 , H04B10/142 , H04B10/18
摘要： The invention relates to a method for compensating, in a coherent optical communication system with heterodyne detection, at the receiving side phase noise of the transmitting and of the local laser. Characteristic of the present method is that the phase-noise compensation takes place in the LF domain. The two MF heterodyne signals (Imf and Pmf) are first demodulated into LF signals (in which there is still noise), which are subsequently substracted from one another, due to which the respective noise components cancel out each other. Preferably a local laser signal which is, qua frequency, between the two other HF signals is chosen. This offers the advantage that the two MF heterodyne signals can be modulated by one and the same demodulator; because for the compensation of phase noise the demodulated MF signals (Ilf respectively Plf) which are, qua phase noise, in opposite phase with regard to each other are then added to one another. The advantage of the method according to the invention is that the bandwidth for which the receiver has to be suitable is relatively small.

12. 发明专利

ES2015841T3 未知
公开(公告)号：ES2015841T3
公开(公告)日：1993-03-16
申请号：ES89203149
申请日：1989-12-08
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： TEUNISSEN, GERARDUS MARIA CLEMENS
IPC分类号： E05D3/06 , E05D3/18

13. 发明专利

CA2042007A1 DIGITAL OPTICAL SWITCH 未知
公开(公告)号：CA2042007A1
公开(公告)日：1991-11-18
申请号：CA2042007
申请日：1991-05-07
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： VAN DER TOL, JOHANNES J. G. M. , DOEKSEN, DOEKE K.
IPC分类号： G02F1/313
摘要： In a digital optical switch which is based on the modeselectivity principle, made up of a passive section (A) containing a first optical wave guide (1) and a second optical wave guide (2) and a switching section (B) containing a third optical wave guide (3) and a fourth optical wave guide (4), both the required asymmetry and the bringing of the optical wave guides within or outside each other's interaction region are achieved with the aid of curves (K1, K2) in said optical wave guides. In the switching section (B) said asymmetry is switchable. Use is made of the effect that a curve results, in general, in a reduction of the propagation constant in the optical wave guide. Suitable curves are of circular-arc shape and sinusoidal. The switching section (B) may furthermore incorporate a short intermediate section (s-u) in which the optical wave guides (12, 13) run straight at a small mutual angle (.PHI.) in the event that the switchable asymmetry is in the first instance too small with a particular choice of material. The invention makes possible much shorter switches which have a greater packing density.

14. 发明专利

CA2024583A1 METHOD FOR MONITORING, BY MEANS OF A MONITORING DEVICE, A DOWNSTREAM TRANSMISSION MEDIUM CONTAINING A MULTIPLICITY OF VIRTUAL, ASYNCHRONOUSLY TIME-SHARED TRANSMISSION CHANNELS 未知
公开(公告)号：CA2024583A1
公开(公告)日：1991-03-06
申请号：CA2024583
申请日：1990-09-04
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： BRANDT, DICK
IPC分类号： H04Q3/00 , H04L12/56

15. 发明专利

DE389062T1 未知
公开(公告)号：DE389062T1
公开(公告)日：1991-02-07
申请号：DE90200673
申请日：1990-03-21
申请人： KONINKLIJKE PTT NEDERLAND N.V., DEN HAAG/'S-GRAVENHAGE, NL
发明人： TAN, HAN HIONG, NL-2651 VD BERKEL EN RODENRIJS, NL
IPC分类号： H04J14/02 , H04Q11/00

16. 发明专利

DE381275T1 未知
公开(公告)号：DE381275T1
公开(公告)日：1990-10-18
申请号：DE90200189
申请日：1990-01-29
申请人： KONINKLIJKE PTT NEDERLAND N.V., DEN HAAG/'S-GRAVENHAGE, NL
发明人： VAN DEN DOOL, FRANS, NL-2264 EB LEIDSCHENDAM, NL , VAN DER WAL, JACOB CORNELIS, NL-2613 VE DELFT, NL
IPC分类号： H04L12/56
摘要： The invention provides a method for transmitting, via a transmission medium with a plurality of virtual, asynchronously time-divided transmission channels, a flow of data, and in particular a method for protecting these transmission channels against an exceeding of the maximum cell frequencies, based on the "leaky bucket"-entrance monitoring method. According to the invention the state of the counter of the relevant channel will be decreased on the arrival of a data cell by a value which is a function of the length of time between the moment of arrival of that data cell and the moment of arrival of a preceding data cell with the same channel indication. The decrease of the state of the counter takes place under the same time regime as the arrival of the data cells. Also the increase of the state of the counter, the comparison of that state of the counter with a threshold value and the switching through or not, dependent on the result of the comparison, of the data cell takes place under the same time regime. Owing to this, the monitoring device can function synchronously with the successively arriving data cells in a completely time-divided way, due to which all the virtual channels can be monitored individually by means of only one such a monitoring device. The value by which the state of the counter is decreased on the arrival of the data cell is preferably the product of a first constant value and said length of time between said two moments of arrival. The invention also comprises a device for carrying out said method and is for that purpose provided with read-out means (1), storage means (3, 5, 7, 9, 12, 14), time indicating means (4), computing means (6, 8, 10, 11, 15), means of comparison (13) and switching means (2).

17. 发明专利

AU637293B2 BUFFER SYSTEM FOR THE TEMPORARY STORAGE OF FLAT OBJECTS SUCH AS LETTERS, AND BUFFER FOR USE IN SAID BUFFER SYSTEM 未知
公开(公告)号：AU637293B2
公开(公告)日：1993-05-20
申请号：AU6668390
申请日：1990-11-15
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： JAN FREDERIK SURINGH , FRANK PIETER VAN POMEREN , HARRO MIJNDERT VAN LEIJENHORST , JOHANNES HENRICUS MARIA BEERMAN
IPC分类号： B65H29/60 , B07C1/02 , B07C3/02 , B07C3/08 , B07C3/20 , B65H5/00
摘要： The invention comprises a buffer system and a buffer (20) applied in it. The buffer acts as mechanical RAM and contains a number of storage pockets (28) for the temporary separate storage of flat articles such as letters for postal processing purposes such as, for example, sorting and video coding. Electromechanically the buffer is such that the letters are not released at any point and are subject to shifting as little as possible, and permit a dense packing of the pockets. This is achieved by using a slide/entrainment conveyance system which is formed by elastic clamping between an endless conveyor (54, 72, 77) with a very high coefficient of friction, for example one or more elastic cords running in parallel and a sliding surface (60, 73, 75) having a very low coefficient of friction both in the sections (21 and 22) of conveyance past the pockets and in the pockets (28). In the pockets, said sliding/entrainment conveyance system is constructed as a separately controllable letter catchment, retainment and ejection device. Each two successive buffer pockets have a partition in common provided with the endless conveyor (54) of one of the said two pockets and the sliding surface (60) of the other of the said two pockets. The buffer system comprises a number of such buffers (20) with or without distributed control. The buffers (20) are situated along a branching feed section (1, 23) in which a gate (20, 26) is sited at every buffer branching point and every connecting point. First process signal connections (6) via which so-called letter logging signals (BBS) are concomitantly transmitted for every letter conveyed along the feed section (1, 23) run in parallel with the branched feed section. Appended to each of said gates (25, 26) is a gate control (91, 38) which determines on the basis of the letter logging signals (BBS) and, for example, the number of free pockets (#-VAKKEN) in each of two gate directions in which direction the letter with its associated letter logging signals (BBS) is sent. Said letter logging signals comprise in all cases a letter identification code (BIC) assigned to the letter by an application control (5) when the letter is fed into the system. The application control continuously makes a selection of letters, which are eligible for discharge from the system, from the instantaneously stored letters on the basis of certain letter features which are derived from the letters to be fed in at the system entrance. Data of the selected letters, including time indications (TI) of when the letters have to pass a defined ejection point (X) in the system exit are transmitted via second process signal connections (9) to the control (38) of each of the buffers (20). Such a buffer system can readily be equipped either as a sorting system or as a video coding system.

18. 发明专利

CA2026872A1 METHOD FOR MONITORING A TRANSMISSION SYSTEM WHICH COMPRISES A PLURALITY OF VIRTUAL, ASYNCHRONOUSLY TIME-SHARED TRANSMISSION CHANNELS VIA WHICH A DATA FLOW CAN BE TRANSMITTED 未知
公开(公告)号：CA2026872A1
公开(公告)日：1991-04-10
申请号：CA2026872
申请日：1990-10-03
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： BRANDT, DICK
IPC分类号： H04L12/56 , H04L69/40
摘要： The data flow is composed of data cells which are each transmitted via one of said transmission channels and which each comprise a control word group containing one or more control words and also an information word group containing one or more information words. A number of variables is maintained which, on arrival of a data cell at a certain location, are each altered in accordance with a alteration algorithm and are then processed in accordance with an evaluation algorithm to produce an evaluation signal. One or more of such evaluation signals are processed in accordance with a combination algorithm to produce a control signal and in which method a data cell is, or is not, transmitted, depending on the value of the control signal. . One of a plurality of quality classes is assigned to each of the data cells and for each quality class, a first variable is maintained which relates to the number of data cells having the respective quality class, which first variable is altered in accordance with a first alteration algorithm when a data cell arrives at a first location (I) and is processed in accordance with a first evaluation algorithm to produce a first evaluation signal. . Each of the virtual transmission channels is divided into one or more groups which each comprise one or more of said transmission channels and which each comprise those virtual transmission channels which make use of a particular potential congestion point in the transmission system and for each group of virtual transmission channels, a second variable is maintained which relates to the number of data cells to be transmitted via the respective group of transmission channels, which second variable is altered in accordance with a second alteration algorithm when a data cell arrives at a second location (I,II,III) and is then processed in accordance with a second evaluation algorithm to produce a second evaluation signal. . Depending on the value of the second evaluation signal and depending on the value of the respective quality class, the first alteration algorithm or the first evaluation algorithm or both are controlled in a manner such that, if the number of data cells of the respective group of channels is relatively large, the number of data cells transmitted is reduced and this will be the more so, the lower the quality class is.

19. 发明专利

CA2026596A1 METHOD FOR TRANSFERRING, BETWEEN TWO SWITCHING EXCHANGES FOR MOBILE SERVICES, THE HANDLING OF AN ACTIVE CONNECTION WITH A MOBILE TERMINAL 未知
公开(公告)号：CA2026596A1
公开(公告)日：1991-04-04
申请号：CA2026596
申请日：1990-10-01
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： HECKER, HUBERTUS P. J.
IPC分类号： H04W36/12

20. 发明专利

DE396186T1 未知
公开(公告)号：DE396186T1
公开(公告)日：1991-02-07
申请号：DE90201063
申请日：1990-04-27
申请人： KONINKLIJKE PTT NEDERLAND N.V., DEN HAAG/'S-GRAVENHAGE, NL
发明人： VAN DE MEENT, NICO, NL-2343 MS OEGSTGEEST, NL
IPC分类号： H04N7/088 , H04N7/087

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