Bit Error Rate Test (BERT) is a test method for testing the bit error rate. BERT tests are performed with bit error rate testers that use predetermined digital loading patterns. In this process, a pattern generator produces the digital test pattern and a receiving device that can receive the pattern.
The two devices can be connected as one unit at one end of the transmission link and connected via loopback, but they can also operate in separate units at both ends of the transmission link. They count the number of bit errors and relate them to the total number of bits transmitted. The ratio is the bit error rate.
In bit error rate tests, there are several commonly used loading patterns. These include the Pseudo Random Binary Sequence( PRBS) and the Quasi Random Signal Sequence( QRSS), which are bit patterns with specified 0-1 combinations such as 3 in 24, 2 in 8, 1:7, All Ones, All Zeros, Alternating 0s and 1s, and several others.