average error rate

In a transmission system, the ratio of (a) the number of incorrect data units, such as binary digits (bits), characters, words, or frames, to (b) the number of the same data units sent correctly, both counted during the same performance measurement period. Note: A data unit is counted as an erroneous unit when one or more bits are different from the bits that are transmitted. Thus, if a block is sent with an erroneous bit, and the block is received exactly as it was sent, with the erroneous bit, it is not counted when determining the average error rate. See also binary digit, bit, block, data unit, error, error rate, performance measurement period, receive, transmit.