PRBS Length

A Pseudo-Random Binary Sequence (PRBS) generates a digital pattern of information, which uses pseudo-noise to make it difficult to predict without knowing the actual sequence-generation algorithm. A PRBS pattern is generated using a Linear-Feedback Shift Register (LFSR) as shown below.

An LFSR is specified by the number of stages it contains and which of those stages ("taps") feed the exclusive-OR (XOR) gate within its feedback network. The PRBS output is taken from the last stage. With properly chosen taps, an L-stage LFSR produces a repetitive PRBS of length 2L–1. The clocking frequency of the LFSR determines the "bit rate" of the PRBS.

Select the PRBS length available for your waveform.

  • P7M1 – 2^7-1 bits
  • P15M1 – 2^15-1 bits
  • P23M1 – 2^23-1 bits
  • P31M1 – 2^31-1 bits