Construction of de Bruijn sequences from product of two irreducible polynomials

We study a class of Linear Feedback Shift Registers (LFSRs) with characteristic polynomial f(x) = p(x)q(x) where p(x) and q(x) are distinct irreducible polynomials in F2[x]. Important properties of the LFSRs, such as the cycle structure and the adjacency graph, are derived. A method to determine a s...

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Bibliographic Details
Main Authors: Chang, Zuling, Ezerman, Martianus Frederic, Ling, San, Wang, Huaxiong
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2017
Subjects:
Online Access:https://hdl.handle.net/10356/83380
http://hdl.handle.net/10220/43538
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Institution: Nanyang Technological University
Language: English
Description
Summary:We study a class of Linear Feedback Shift Registers (LFSRs) with characteristic polynomial f(x) = p(x)q(x) where p(x) and q(x) are distinct irreducible polynomials in F2[x]. Important properties of the LFSRs, such as the cycle structure and the adjacency graph, are derived. A method to determine a state belonging to each cycle and a generic algorithm to find all conjugate pairs shared by any pair of cycles are given. The process explicitly determines the edges and their labels in the adjacency graph. The results are then combined with the cycle joining method to efficiently construct a new class of de Bruijn sequences. An estimate of the number of resulting sequences is given. In some cases, using cyclotomic numbers, we can determine the number exactly.