Bit error ratio
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In telecommunication, an error ratio is the ratio of the number of bits, elements, characters, or blocks incorrectly received to the total number of bits, elements, characters, or blocks sent during a specified time interval.
The most commonly encountered ratio is the bit error ratio (BER).
Note: For a given communication system, the bit error ratio will be affected by both the data transmission rate and the signal power margin.
Note 1: Examples of bit error ratio are (a) transmission BER, i.e., the number of erroneous bits received divided by the total number of bits transmitted; and (b) information BER, i.e., the number of erroneous decoded (corrected) bits divided by the total number of decoded (corrected) bits.
Note 2: The BER is usually expressed as a coefficient and a power of 10; for example, 2.5 erroneous bits out of 100,000 bits transmitted would be 2.5 out of 105 or 2.5 × 10-5.
Note 3: On good connections you have an BER below 10E-9. The test time for a 95% confidence Level on a:
STM-256 / OC-768 = 1 s
STM-64 / OC-192 = 3 s
STM-16c / OC-48c = 12 s
STM-4c / OC-12c = 48 s
STM-1 / OC-3 = 3.2 min
Bit Error Rate tests use patterns, such as 511, 2047, and QRSS when conducting tests.
Source: from Federal Standard 1037C and from MIL-STD-188 de:Bitfehlerhäufigkeit it:BER