Bipolar violation
Encyclopedia
A bipolar violation, bipolarity violation, or BPV, is a violation of the bipolar encoding
rules where two pulse
s of the same polarity occur without an intervening pulse of the opposite polarity. This indicates an error in the transmission
of the signal.
T-carrier
and E-carrier
signals are transmitted using a scheme called bipolar encoding, a.k.a. Alternate Mark Inversion (AMI), where a ONE is represented by a pulse, and a ZERO is represented by no pulse. Pulses (which represent ones) always alternate in polarity, so that if, for example two positive pulses are received in succession, the receiver knows that an error occurred (a violation) in that one or more bits were either added or deleted from the original signal.
Reliable transmission of data using this scheme requires a regular stream of pulses; too many zero bits in succession can cause a loss of synchronization between transmitter and receiver. To ensure that this is always present, there exist a number of modified AMI code
s which use judiciously placed bipolar violations to encode long string
s of consecutive zeroes.
Bipolar encoding
In telecommunication, bipolar encoding is a type of line code . A duobinary signal is such an encoding.- Advantages :...
rules where two pulse
Pulse (signal processing)
In signal processing, the term pulse has the following meanings:#A rapid, transient change in the amplitude of a signal from a baseline value to a higher or lower value, followed by a rapid return to the baseline value....
s of the same polarity occur without an intervening pulse of the opposite polarity. This indicates an error in the transmission
Transmission (telecommunications)
Transmission, in telecommunications, is the process of sending, propagating and receiving an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless...
of the signal.
T-carrier
T-carrier
In telecommunications, T-carrier, sometimes abbreviated as T-CXR, is the generic designator for any of several digitally multiplexed telecommunications carrier systems originally developed by Bell Labs and used in North America, Japan, and South Korea....
and E-carrier
E-carrier
In digital telecommunications, where a single physical wire pair can be used to carry many simultaneous voice conversations by time-division multiplexing, worldwide standards have been created and deployed...
signals are transmitted using a scheme called bipolar encoding, a.k.a. Alternate Mark Inversion (AMI), where a ONE is represented by a pulse, and a ZERO is represented by no pulse. Pulses (which represent ones) always alternate in polarity, so that if, for example two positive pulses are received in succession, the receiver knows that an error occurred (a violation) in that one or more bits were either added or deleted from the original signal.
Reliable transmission of data using this scheme requires a regular stream of pulses; too many zero bits in succession can cause a loss of synchronization between transmitter and receiver. To ensure that this is always present, there exist a number of modified AMI code
Modified AMI code
Modified AMI codes are Alternate Mark Inversion line codes in which bipolar violations may be deliberately inserted to maintain system synchronization. There are several types of modified AMI codes, used in various T-carrier and E-carrier systems....
s which use judiciously placed bipolar violations to encode long string
String (computer science)
In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set or alphabet....
s of consecutive zeroes.