U.S. Philips Corporation

Leonardus M Driessen

Cornelis Pieter Janse

Constant P Baggen

Lodewijk B Vries

Paul D Lahaije

Rudy W Pollen

A topological network, comprising a set of 0-cells (nodes) (28, 29) interconnected by a set of 1-cells (aa, bb, . . . , gg).sub.1 is divided into sections (E, F, G) corresponding to discrete parcels of data for storage in a mass memory such as a CD-ROM. A boundary node (28, 29) is defined at each point where the network traverses a boundary between sections. The parcel of data for a given section includes a chain list record for each 1-cell in the section, which chain list record generally refers directly (TP) to a further 1-cell in the network terminating at the same node. However, no chain list record refers directly to a 1-cell outside the section of the network to which the data parcel relates. An indirect reference (0-C') across the section boundary can be made easily, while an overall saving in data volume is obtained compared with a known method. Further information can be introduced into the data parcels by ordering techniques, enabling the network data to be used in a particularly efficient and systematic manner.

Method of storing a topological network, and methods and apparatus for

A method of storing in a memory digital data representing a topological network having a set of nodes (0-cells), segments (1-cells), and areas (2-cells) within concatenated 1-cells. For each 1-cell there are stored an associated first 0-cell and second 0-cell and also a thread pointer assigned to the 0-cells. The thread pointer of an 0-cell indicates the next-following 1-cell obtained by rotating the 1-cell in question in a predetermined direction of rotation around such 0-cell. For finding a 2-cell, use is made of a first 1-cell and the thread pointer associated with one of its 0-cells is followed after which, starting from the newly found 1-cell, each time the thread pointer of the opposite 0-cell is used until the first 1-cell is found again.

Method and apparatus for storing digital data representing a topological

A database is stored in a mass memory. For this purpose, it is first divided into main cells and then into base cells according to a predetermined regular division pattern. Each base cell is then checked to see whether its data content is sufficient to occupy substantially completely a storage parcel having a predetermined capacity. If this is the case, the base cell is thus accommodated in a storage parcel; if this is not the case, adjacent base cells are grouped until a storage parcel is occupied substantially completely. The operation of addressing a storage parcel is effected by the use of a main cell table in which address pointers are stored, each of which points to a base cell table. In the base cell table, an index is given for each base cell and this index indicates in which storage parcel the relevant base cell is accommodated. Each of these indices indicates a location in a data paracel list at which an address indicator is present, which indicates the location at which the relevant parcel is stored in the mass memory.

Method for storing a parcelwise divided digital data base as well as of

For the decoding of a data stream which is word-wise protected against errors by a double Reed-Solomon code with symbol-wise interleaving over the code words, first the reliability information for the constituent symbols is aggregated for a code word. Therefrom the strategy is determined, entailing the number of erase symbols and the maximum number of error symbols to be corrected. The correction result is compared with a reliability code and on the basis thereof all symbols obtain an at least trivalent secondary reliability indication for decoding in the second code.

Decoding device for code symbols protected by Reed-Solomon code

A decoding device for code words which are protected against the occurrence of several symbol errors per code word by means of a Reed-Solomon code is provided with a word buffer which comprises a space for the storage of an erasure indication per symbol received. For correction of the code word, first the syndrome symbols are formed by multiplication by the parity check matrix. The sum of twice the number of error symbols and once the number of erasure symbols may not be larger than the number of syndrome symbols. First the syndrome symbols are modified so that the syndrome symbols which could possibly relate to error symbols (non-erasure symbols) are no longer influenced by the erasure symbols. The key equation and error locator equation for the non-influenced syndrome symbols can then be separately solved, so that the locations of error symbols can be found. The latter syndrome symbols are then modified, when necessary, for calculated error locations, while the error values or erasure values are determined from a set of mutually independent syndrome symbols whose number equals the sum of error symbols and erasure symbols. There is provided an arithmetic unit for the Galois-field which, for the sake of simplicity, performs the calculations on the exponents of the symbols which are written as powers of the basic symbol of the Galois-field.

Fast decoder and encoder for Reed-Solomon codes and recording/playback

An error protection code which acts on subpictures for the transmission of television picture information. First the picture is subpicture-wise transformed (124) by means of transformation functions, for example, Hadamard functions. Of the coefficients thus formed, a number of most significant coefficient bits which are associated with low frequency transformation functions are protected against a bit error (126). Moreover, a comparatively small number of coefficient bits within said number are protected against an additional bit error.

System for decoding and displaying encoded television pictures

An error protection code which acts on subpictures together constituting a television picture for the transmission of data for reconstructing the television picture at the receiving end. First each subpicture transformed by, Hadamard functions. Of the coefficients thus formed, a number of most significant coefficient bits which are associated with low frequency transformation functions are protected against a bit error. Moreover, a comparatively small number of coefficient bits within said number are protected against an additional bit error.

Growing community of inventors

Eindhoven, Netherlands

Leonardus M Driessen