Digital signal multiplex apparatus.

p0001The invention relates to a digital signal multiplex device with at least one multiplexer and at least one demultiplexer for pulse frame with a plurality of user information channels.

p0002Such devices are known, for example, from the journal "telecom report", 2 (1979) Supplement to digital transmission technology, pages 46-51 and 59-64. Pulse frame for this are in the CCITT Yellow Book, Vol.III, Fascicle 111.3, "Digital Networks - Transmission Systems and Multiplexing Equipment", Recommendation G.751, pages 144 to 155..

p0003In today's analog telephone network about ten percent of the transmission capacity for data transmission are used. A similar order of magnitude can also be expected in a future digital network. For economic reasons, the transmission quality of the analog telecommunications network was adapted to the demands of the voice traffic. For data transmission, a much higher transmission quality is required, which was taken into account, for example, by coding and data security in the terminals.

p0004Also, the future digital network will need to be adjusted for economic reasons the demands of the voice traffic. In the transmission of data and image signals characterized arrangements will be necessary in order to ensure the necessary when these signals better transmission quality in the digital telecommunication network. One can apply to those known from the data transmission methods such as a corresponding error-insensitive coding in the terminal.

p0005According to the book of Swoboda ⁿCoding for error correction and error detection ", R. Oldenbourg Verlag, Munich-Vienna, 1973 can be achieved a backup when a source code is converted into a redundant representation having more binary digits. An encryption of the message by code words of a fixed length of n digits is called block coding. These n points contained m news sites and k checkpoints. the latter are determined the error control code from the m news agencies according to an agreed procedure. the receiving side recognize or even correcting erroneous code words and the reshaping of the messages to the original source code is referred to as decoding ,

p0006An error control code is an example of of "IEEE Trans.," IT-16 (₁₉₇0) 9, pages 649-650 known Fire Code.

p0007Object of the invention is to provide for the digital network while maintaining the voice traffic matched transmission quality, a solution, a higher transmission quality, ie smaller Bitfehlerquoten be achieved with only the data transmission channels, without departing tragngssysteme the standardized hierarchical levels for the transfer. Starting from a digital signal multiplexing device with at least one multiplexer and at least one demultiplexer for pulse frame with several user information channels, this object is achieved in that a Datensicherungscoder is provided which is associated with the multiplexer, detects errors and one or more user information channels or integral parts of at least a Nutzinformationskanals with backup information has and that a data backup decoder is provided which is associated with the demultiplexer, the data protection information is supplied and which performs error correction.

p0008It is advantageous if a backup for at least part of the user information channels is provided is.

p0009It is also advantageous when a Datensicherungscoder and a backup decoder are provided, which derive their synchronization block of the frame synchronization of the multiplexer and the demultiplexer.

p0010In the digital signal multiplexing apparatus according to the invention all known error control codes can be used for backup in principle. Block codes, however, can better adapt to the block structure of the pulse frame and the synchronization.

p0011The digital signal multiplexing apparatus according to the invention make it possible in a future digital network with transmission systems that are designed for voice traffic, such as single 34-Mbit / s bundle with substantially lower Bitfehlerquoten (for example, 10^-10) to obtain. It is possible that the protected data bundles over more common multiplexer in transmission systems with higher hierarchical levels as 140 Mbit / s to be inserted. Cascading the digital signal multiplexing apparatus according to the invention in even higher levels of the hierarchy brings an even better transmission quality. There are, for example cable, radio relay, satellite and fiber optic transmission systems in question.

p0012The inventive solution can be switched to a future digital telephone network without changing the quality of the transmission equipment, a part of the channels for example, the data traffic with higher transmission quality. This type of backup (for example, 6%) produces a better channel quality, without leaving the standardized hierarchical levels at the expense of a small portion of the channel capacity.

p0013On the basis of embodiments, the invention is explained in more detail below.

p0014<ul><li>Fig. 1 shows a cascade of known digital signal multiplex devices,</li><li>Fig. 2 shows a pulse frame for an 8-Mbit / s digital signal,</li><li>Fig. 3 shows a pulse setting for a 34-Mbit / s digital signal,</li><li>Fig. 4 shows a section of a 34-MOIT / s pulse frame with data protection information</li><li>Fig. 5 shows a first variant of the digital signal multiplexing apparatus according to the invention and</li><li>Fig. 6 shows a second variant of the erfindungsgemäβen Digital signal multiplexing unit.</li></ul>

p00151 shows a cascade of three well-known digital signal multiplex devices. The digital signal multiplexing apparatus DSMX 2/8 sets of four 2 Mbit / s signals in an 8-Mbit / s signal to the digital signal multiplexing apparatus DSMX 8/34 sets of four 8-Mbit / s signals in a 34-Mbit / s signal and to the digital signal multiplexing apparatus DSMX 34/140 finally sets four 34-Mbit / s signals into a 140-Mbit / s signal.

p0016Figure 2 shows the standardized by CCITT pulse frame for the 8-Mbit / s digital signal, and Figure 3 for the 34-Mbit / s digital signal. Each pulse frame is divided into four blocks 1 through IV. With NI user information channels, denoted by St Stopfinformationen with B stuffing or bits of information with RKW frame alignment words and SB service bits. The numbers in the blocks represent bits.

p0017Figure 4 relates to the use of a 2-Mbit / s channel for the data protection information. Dine in Figure 1 in the digital signal multiplexing apparatus DSMX 2/8 in the fourth input, ie, a data protection information in the Nutzinformationskanal NI of Block IV of the pulse frame of Figure 2, then it will appear in the in Figure 4 partially represented 34 Mbit / s multiplexing frame on the shaded places.

p0018Figure 5 shows a transmitting part 1 to 3 and a receiving part 5 to 10 of a digital signal multiplexing apparatus of the invention. The transmitting part 1 to 3 and the receiving part 5 to 10 are connected by a chain 4 of transmission systems. Reference numerals 1 and 10 "TELCOM REPORT" known digital signal multiplexing device DSMX are from the aforementioned magazine 64 called K / 2 with the numeral 2 and 9 known from the same literature reference digital signal multiplexing device DSMX 2/8. The reference numeral 3 represents a Datensicherungscoder and numerals 5 to 8 for securing a data decoder. The latter consists of an integrated circuit 5 with the same type name as that of the integrated circuit 3, a correction circuit 6, a delay circuit 7 and a modulo-2 adder 8. The transmit lines designated with syn synchronization signals.

p0019To the digital signal multiplexing apparatus 1, three 64-kbit / s signals and to the digital signal multiplexing apparatus 2, three 2-Mbit / s signals, as well as the 2-Mbit / s output signal of the digital signal multiplexer 1 can be created. The output signal of the digital signal multiplexing apparatus 2 passes through the Datensicherungscoder 3. This derives from one or more of the interleaved input signals check bits, which are supplied as 64-kbit / s signal to the digital signal multiplexing apparatus 1 and after formation of the output signal of the digital signal multiplexing apparatus 2 find their place in the shaded areas in Fig. 4. So that at the receiving end an error correction can be carried out, the useful signal is delayed from the backup information to one or more backup block lengths.

p0020In the reception part of the data and the backup information on the integrated circuit 5 through the delay circuit 7 a delay of one or more backup block lengths and the modulo-2 adder 8 to the digital signal multiplexing unit 9. In this and the data signal multiplexing unit 10, the separated data protection information and supplied to the integrated circuit. the data and the backup information of the control circuit 6 are meantime parallel fed, which examines the data and the data protection information on errors. Their output signals corrected on the modulo-2-adder 8 possible errors in Hauptnachrichtenfluß.

p0021The operation of the integrated circuits 3 and 5 and the control circuit 6 are described in the data sheet Am9520 of Advanced Micro Devices, Inc. of Feb. 1981st

p0022Figure 6 shows an arrangement in which the data backup is carried out before the multiplexer and after the demultiplexer. The transmitting part comprises the elements 11 to 18 and the receiving part of the elements 20 to 37. transmitting element and receiving element are connected by a transmission path 19 or a chain 19 of transmission systems connected.

p0023By the reference numeral 11 to 13 integrated circuits of the already mentioned type Am9520 are designated. Numerals 14 and 15 refer to any necessary delay elements, and numeral 16 denotes a data information multiplexer.

p0024With 22 to 24, 27, 31 and 35 delay circuits are identified, integrated circuits of the type Am9520 bear the reference numerals 26, 30 and 34, to control circuits refer the reference numerals 25, 29 and 33, modulo-2 adders 28, 32 and 36 denotes a data information demultiplexer is designated by 37th

p0025In this embodiment, three 8-Mbit / s-inputs of the data backup are subjected. The 8-Mbit / s signals through acting as Datensicherungscoder integrated circuits 11 to 13, respectively, indicating a backup information to the backup multiplexer 16 from. cause any existing delay circuits 14 and 15 that the backup information will not be achieved simultaneously. The backup data multiplexer 16 forms from the data backup information, a time division multiplexed signal and feeds this into the fourth 2-Mbit / s input of the digital signal multiplexing apparatus 17th This is in turn a synchronizing syn back. The digital signal multiplexing unit 18 adds the three 8-Mbit / s signals and the output signal of the digital signal multiplexing apparatus 17 together.

p0026On the receiving side the digital signal multiplexing apparatus of the 8 Mbit / s signals 20 separates again. The first three pass through delay circuits 22 to 24 in data signal decoder, as already described in FIG. 5. The fourth 8-Mbit / s signal of the digital signal multiplexing apparatus 20 is to the digital signal multiplexing apparatus 21 is supplied and separated into 2 Mbit / s signals. The fourth of these is the Datensicherungsinformations- demultiplexer 27 is supplied, which separates the three backup information and supplies individually the integrated circuits 26, 30 and 34th For proper function of this Datensicherengsinformationsdemultiplexers 37 must also receive a synchronizing signal sy-n from the digital signal multiplexing apparatus 21st The integrated circuits 26, 30 and 34 are synchronized by the digital signal multiplexing apparatus 20 of.

p0027In the US, anada and Japan takes the place a bit rate of 2.048 Mbit / s such a 1.544 Mbit / s and the place a bit rate of 8.448 Mbit / s, a solche__von 6.312 Mbit / s. In these countries, a backup information without Nutzinformationsverlust can be transferred when using a European transmission system of higher bit rate, and then the superfluous for Nutzinformationsübertragung slots are occupied in the frame with the data protection information.