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1. 发明专利

AU3027992A SYSTEM FOR ENCODING DATA PRESENTED WITH A FIRST CODING DEVICE AND FOR DECODING ENCODED DATA WITH A SECOND CODING DEVICE, AND CODING DEVICE FOR USE IN THE SYSTEM 未知
公开(公告)号：AU3027992A
公开(公告)日：1993-06-24
申请号：AU3027992
申请日：1992-12-18
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： JEAN PAUL BOLY , MARTIN KLAAS DE LANGE , GERRIT JAN VAN LOO , GERRIT ROELOFSEN
IPC分类号： H03M13/00 , H04J13/00 , H04L7/00 , H04L9/12 , H04L25/03
摘要： In a system for de-/encoding data using (de)coding devices at either end of a transmission channel, the data sometimes comprise additional synchronisation information which is used to reduce the effect of faults in the transmission channel. If this synchronisation information is not already present, it is impossible in certain cases to add such information. The invention provides a system which, regardless of the presence of additional synchronisation information, is able to reduce the effect of faults. For this purpose, each (de)coding device is provided with means for comparing sequences of encoded data with at least one predetermined code word and for setting the associated coding device to a reset state in the event of equality. Because the predetermined code word repeats statistically in the encoded data, a fault adversely affects the decoding for not more than one time interval.

2. 发明专利

ES2004853T3 未知
公开(公告)号：ES2004853T3
公开(公告)日：1992-04-01
申请号：ES88200793
申请日：1988-04-26
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： GRIFFIOEN, WILLEM , DE JONG, CORNELIS LEENDERT
IPC分类号： G02B6/46 , G02B6/44 , G02B6/50 , H02G20060101 , H02G1/08

3. 发明专利

DE388537T1 未知
公开(公告)号：DE388537T1
公开(公告)日：1991-01-17
申请号：DE89203336
申请日：1989-12-29
申请人： KONINKLIJKE PTT NEDERLAND N.V., DEN HAAG/'S-GRAVENHAGE, NL
发明人： SMULDERS, PETRUS FRANCISCUS MARIA, NL-5508 DC VELDHOVEN, NL
IPC分类号： G01R29/00 , H04L25/02 , H03K5/08 , H03K5/19

4. 发明专利

CA2008648A1 METHOD FOR TRANSMITTING, VIA A PLURALITY OF ASYNCHRONOUSLY TIME-DIVIDED TRANSMISSION CHANNELS, A FLOW OF DATA CELLS, THE STATE OF A COUNTER FOR EACH TRANSMISSION CHANNEL BEING KEPT UP TO DATE IN ACCORDANCE WITH THE NUMBER OF DATA CELLS PER UNIT OF TIME 未知
公开(公告)号：CA2008648A1
公开(公告)日：1990-08-03
申请号：CA2008648
申请日：1990-01-26
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： DOOL, FRANS V. D. , WAL, JACOB C. V. D.
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).

5. 发明专利

DE317030T1 未知
公开(公告)号：DE317030T1
公开(公告)日：1989-08-03
申请号：DE88202581
申请日：1988-11-17
申请人： KONINKLIJKE PTT NEDERLAND N.V., LEIDSCHENDAM, NL
发明人： PRINS, GEERT JAN, NL-2625 GP DELFT, NL
IPC分类号： B65H31/06 , B65H29/46 , B65H31/26

6. 发明专利

AU2729092A METHOD FOR AUTHENTICATING COMMUNICATION PARTICIPANTS, SYSTEM FOR APPLICATION OF THE METHOD AND FIRST COMMUNICATION PARTICIPANT AND SECOND COMMUNICATION PARTICIPANT FOR APPLICATION IN THE SYSTEM 未知
公开(公告)号：AU2729092A
公开(公告)日：1993-04-29
申请号：AU2729092
申请日：1992-10-23
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： KLAAS PIETER VLIEG , JURGEN JACOB SPAANDERMAN , MARIA LEO WENAS
IPC分类号： H04B7/204 , G09C1/00 , H04L9/08 , H04L9/16 , H04L9/32
摘要： Known methods for authenticating communication participants add a code word to a command signal, which code word is a crytographic function of the command signal and a key value which in its turn is a function of a master key value and a change code word. The master key value has a permanently fixed value, in contrast to the change code word which serves to change the key value. The method according to the invention makes use of a key value which is a function of at least one previous key value, the master key value with the permanently fixed value, which, once it has been discovered or leaked, substantially weakens the encryption, no longer being required.

7. 发明专利

ES2000080T3 未知
公开(公告)号：ES2000080T3
公开(公告)日：1993-02-16
申请号：ES87200171
申请日：1987-02-04
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： PALM, MICHIEL
IPC分类号： H05K9/00 , H02H9/04 , H02H9/06 , H03H7/01 , H03H7/075 , H04B15/00

8. 发明专利

ES2008841T3 未知
公开(公告)号：ES2008841T3
公开(公告)日：1992-07-16
申请号：ES88202582
申请日：1988-11-17
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： DIEMEER, MARTINUS BERNARDUS JOHANNES
IPC分类号： G02B6/12 , G02F1/065 , G02F1/29 , G02F1/313

9. 发明专利

CA2051020A1 OPTICAL TRANSMISSION NETWORK WITH FREQUENCY LOCKING MEANS 未知
公开(公告)号：CA2051020A1
公开(公告)日：1992-03-12
申请号：CA2051020
申请日：1991-09-10
申请人： KONINKLIJKE PTT NEDERLAND N.V.
发明人： VAN DEVENTER, MATTIJS O. , BEKOOIJ, JOHAN P.
IPC分类号： H04B10/20 , H04B10/155
摘要： Frequency stabilizing in a, for instance star/branched-tree shaped, network can be well executed by locking the frequencies (f1) of the transmitters (T1) in the network centre to a common reference frequency source (CFC) and, moreover, per duplex connection, locking (at a fixed frequency distance) the frequency (f2) of the subscriber's transmitter (T2) to the transmission signal (t1) as received from the network centre's transmitter (T1). Per duplex connection only the subscriber's local oscillator (L2) has to be tuned so that the transmission signal from the network centre is received optimally. If the subscriber's local oscillator is tuned thus and the subscriber transmitter's frequency has the right frequency offset to the tuned local oscillator frequency (f4), at the network centre's side, signals from the subscriber's transmitter will be received optimally too if the local oscillator (L1) of the network centre's receiver (R1) is set at a certain (predetermined) frequency offset to the signal transmitted to the subscriber's receiver. Frequency setting, at the network centre's side and at the subscriber's side, can be executed by means of auxiliary receivers (R1a,R2a) and AFC-units, generating the various frequency control signals, or by means of the receivers (R1,R2) already in use, provided with multiple pass filters and AFC-units. For achieving relative low IF frequencies, certain frequency orders are preferred.

10. 发明专利

DE399587T1 未知
公开(公告)号：DE399587T1
公开(公告)日：1991-02-28
申请号：DE90201136
申请日：1990-05-21
申请人： KONINKLIJKE PTT NEDERLAND N.V., DEN HAAG/'S-GRAVENHAGE, NL
发明人： BOLY, JEAN PAUL, NL-2381 BL ZOETERWOUDE, NL , ROELOFSEN, GERRIT, NL-2805 DD GOUDA, NL
IPC分类号： H04L9/06

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