N-sequence

(a) is the output of a linear shift register, and

(b) has the property that, if the shift register is set to any nonzero state and then cycled, a pseudorandom binary sequence of a maximum of n = 2^m -1 bits will be generated, where m is the number of stages, i.e. , the number of bit positions in the register, before the shift register returns to its original state and the n-bit output sequence repeats.

Note: The register may be used to control the sequence of frequencies for a frequency-hopping spread spectrum transmission system or modulate the carrier in a direct-sequence spread spectrum system.

Source: from Federal Standard 1037C