PRBS -Pseudorandom bit sequence is just a "highly random" sequence with completely no correlation with adjacent bits... It may be considered equivalent to "noise" since the autocorrelation is a Kronecker delta function...
If i have an n-bit LFSR, with an initial state being one out of 2^n - 1 states except "all zero sate", i can maximally generate a PRBS by modifying the taps of the LFSR... The PRBS sequence repeats after all states have completed, hence it is "pseudo-random"... This is the fundamental behind the generation of CA codes or gold codes, use din CDMA and GPS systems...