Method and device for selecting information usable by a local unit connected to a digital transmission system
First Claim
1. Method of selecting digital information to be transmitted to a local unit originating from at least one independent transmission line and in the form of messages sent sequentially and organized in such a way as to comprise useful information preceded in time by selection information, the method including the following steps:
- cyclical scanning at a fixed frequency of a programmed list of conditions in memory;
simultaneous acquisition of information on said transmission line;
activation of a selection process each time that the selection information of a message received on said transmission line has been acquired, the selection process including a synchronization stage which waits for the scanning process to cross the start of said list of conditions, a comparison (pattern matching) sequence on the selection information contained in the message being received, and a production of a selection variable which indicates if the message being received is of interest to said local unit or not, the selection process ending either when all the conditions from said list have been exhausted and on returning to the start of list condition or upon reading a special end of list code;
memorization of messages selected in a buffer accessible to said local unit.
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Accused Products
Abstract
A method of selecting information usable by a local unit connected to a digital transmission system includes cyclical scanning at fixed frequency of a list of programmed conditions stored in memory, acquisition of information on the transmission channels and activation of a selection process each time that the selection information of a message has been acquired. The selection process comprises a synchronization stage which waits for the scanning process to cross the start of the list of conditions. In a comparison sequence the selection information is compared with the conditions of the list. A selection variable is produced indicating if the message being received is of interest to the local unit or not. The method may be implemented through the use of a highly integrated interface.
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Citations
10 Claims
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1. Method of selecting digital information to be transmitted to a local unit originating from at least one independent transmission line and in the form of messages sent sequentially and organized in such a way as to comprise useful information preceded in time by selection information, the method including the following steps:
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cyclical scanning at a fixed frequency of a programmed list of conditions in memory; simultaneous acquisition of information on said transmission line; activation of a selection process each time that the selection information of a message received on said transmission line has been acquired, the selection process including a synchronization stage which waits for the scanning process to cross the start of said list of conditions, a comparison (pattern matching) sequence on the selection information contained in the message being received, and a production of a selection variable which indicates if the message being received is of interest to said local unit or not, the selection process ending either when all the conditions from said list have been exhausted and on returning to the start of list condition or upon reading a special end of list code; memorization of messages selected in a buffer accessible to said local unit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Device for selecting digital information to be transmitted to a local unit originating from at least one independent transmission line and in the form of messages sent sequentially and organized in such a way as to comprise the useful information preceded in time by selection information, which device comprises, interconnected by an internal bus:
- a receive unit connected to said transmission line by a demodulator and comprising a buffer;
an interface to said local unit;
a data management circuit coupled with a random access memory;
a pattern matching message recognition device looking for coincidence between the selection information of the messages being received on said transmission line and label trap codes stored in an area of said random access memory, the label trap codes forming a condition list and being presented sequentially by a label trap pointer;
said device further comprising a control unit connected to an address generator coupled with said random access memory through a receive pointer, and said label trap pointer, said control unit driving said address generator through said receive pointer and said label trap pointer. - View Dependent Claims (9, 10)
- a receive unit connected to said transmission line by a demodulator and comprising a buffer;
Specification