Bipolar encoding

number, as represented in bipolar encoding, known as AMI (Alternate mark inversion), where : In telecommunication, bipolar encoding is a type of return-to-zero (RZ) line code, where two nonzero values are used, so that the three values are +, −, and zero. Such a signal is called a duobinary signal. Standard bipolar encodings are designed to be DC-balanced, spending equal amounts of time in the + and − states. The reason why bipolar encoding is classified as a return to zero (RZ) is that when a bipolar encoded channel is idle the line is held at a constant "zero" level, and when it is transmitting bits the line is either in a +V or -V state corresponding to the binary bit being transmitted. Thus, the line always returns to the "zero" level to denote optionally a separation of bits or to denote idleness of the line.

number, as represented in bipolar encoding, known as AMI (Alternate mark inversion), where : ]] In telecommunication, bipolar encoding is a type of return-to-zero (RZ) line code, where two nonzero values are used, so that the three values are +, −, and zero. Such a signal is called a duobinary signal. Standard bipolar encodings are designed to be DC-balanced, spending equal amounts of time in the + and − states. The reason why bipolar encoding is classified as a return to zero (RZ) is that when a bipolar encoded channel is idle the line is held at a constant "zero" level, and when it is transmitting bits the line is either in a +V or -V state corresponding to the binary bit being transmitted. Thus, the line always returns to the "zero" level to denote optionally a separation of bits or to denote idleness of the line. ==Error detection== Another benefit of bipolar encoding compared to unipolar is error detection. In the T-carrier example, the bipolar signals are regenerated at regular intervals so that signals diminished by distance are not just amplified, but detected and recreated anew. Weakened signals corrupted by noise could cause errors, a mark interpreted as zero, or zero as positive or negative mark. Every single-bit error results in a violation of the bipolar rule. Each such bipolar violation (BPV) is an indication of a transmission error. (The location of BPV is not necessarily the location of the original error).

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