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2 binary 1 quaternary (2B1Q)

2B1Q (2 Binary, 1 Quaternary) coding is a quaternaryline coding in which two bits, equivalent to one dibit, are converted to a four-level (quaternary) signal, halving the step rate on the line.

2B/1Q coding

2B/1Q coding

In this conversion, a two-bit word is converted to a quaternary symbol, where the first bit is interpreted as a sign, and the second bit (LSB) is interpreted as amplitude. Thus, the binary combination 10 becomes the quaternary symbol +3, 11 becomes +1, 01 becomes -1 and 00 becomes -3. The 2B1Q method is suitable for High Bitrate Digital Subscriber Line (HDSL) and for the VDSL method (Very High Speed Digital Subscriber Line), but is also used with ISDN, namely for the transmission of the primary multiplex rate of 2.048 Mbit/s. A further reduction of the step rate can be achieved by splitting the data stream into two channels.

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Englisch: 2 binary 1 quaternary - 2B1Q
Updated at: 25.08.2011
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