Data transmission system for synchronously transmitting an auxiliary bitstream within a main bitstream
First Claim
1. Data transmission system for transmission of a main bitstream to additionally transmit an auxiliary bitstream together with said main bitstream, said data transmission system comprising a transmitter includingframe means for arranging said main bitstream in superframes, each of said superframes including a plurality of periodically occurring blocks, each of said blocks having a block length of Y bits, where Y is a predetermined integer greater than 1,encoding means for encoding each of said blocks of Y bits according to a respective coding law such that any block of Y bits may be selectively encoded with either a first or a second coding law and a block encoded with the second coding law violates the first coding law, andmeans for determining said respective coding law as a function of the value of at least one corresponding information unit of said auxiliary bitstream, whereby the auxiliary bitstream is transmitted synchronously with the main bitstream, independent of the data content of the main bitstream.
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Abstract
A data transmission system is proposed in which an auxiliary bitstream of low bitrate (AUX) is coded together with a main bitstream of high bitrate (PRIM) without increasing the transmission rate above the high bitrate. This auxiliary bitstream (AUX) is moreover transmitted synchronously with the main bitstream (PRIM). Transmitter (T) divides the main bitstream (PRIM) in periodically occurring blocks of Y bits and codes one bit of the auxiliary bitstream (AUX) in each of the blocks by using a first (AMI) or a second (VAMI) coding law according to the binary value of that bit. The second law is constructed by violating the first coding law (AMI) according to a predetermined violation law. Redundancy in the first coding law (AMI) is used to introduce symbol sequences not permitted under this first coding law (AMI) and to so obtain the second coding law (VAMI).
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Citations
18 Claims
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1. Data transmission system for transmission of a main bitstream to additionally transmit an auxiliary bitstream together with said main bitstream, said data transmission system comprising a transmitter including
frame means for arranging said main bitstream in superframes, each of said superframes including a plurality of periodically occurring blocks, each of said blocks having a block length of Y bits, where Y is a predetermined integer greater than 1, encoding means for encoding each of said blocks of Y bits according to a respective coding law such that any block of Y bits may be selectively encoded with either a first or a second coding law and a block encoded with the second coding law violates the first coding law, and means for determining said respective coding law as a function of the value of at least one corresponding information unit of said auxiliary bitstream, whereby the auxiliary bitstream is transmitted synchronously with the main bitstream, independent of the data content of the main bitstream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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16. Data transmission system according to claim 13, wherein
said violation word contains at least a first balancing bit which is either a mark or a zero such that subsequent violation are of opposite polarity; - and
said violation word contains at least one zero separating said violation from a preceding symbol which can be a mark, and said third coding law is of the HDB4 type, according to which a string of 5 zeroes is substituted by a code word L000V, where V is said violation and L is a second balancing bit determined according to the following table
space="preserve" listing-type="tabular">______________________________________ L previous M previous V ______________________________________ - + + 0 + - 0 - + + - - ______________________________________
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17. Data transmission system according to claim 16, wherein said auxiliary bitstream comprises different multiplexed channels, a specific channel being coded in respective specific blocks of Y bits within said superframe.
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18. Data transmission system according to claim 1, wherein said auxiliary bitstream comprises different multiplexed channels, a specific channel being coded in specific blocks of Y bits within said superframe.
Specification