itpp::LFSR Class Reference

Binary Linear Feedback Shift Register (LFSR). More...

#include <itpp/comm/sequence.h>

List of all members.

Public Member Functions
	LFSR (void)
	Constructor.
	LFSR (const bvec &connections)
	Input connect_polynomial=1+g1*D+g2*D^2+...+gr*D^r in bvec format [g0,g1,...,gr].
	LFSR (const ivec &connections)
	Input connect_polynomial=1+g1*D+g2*D^2+...+gr*D^r in octal format.
void	set_connections (const bvec &connections)
	Input connect_polynomial=1+g1*D+g2*D^2+...+gr*D^r in bvec format [g0,g1,...,gr].
void	set_connections (const ivec &connections)
	Input connect_polynomial=1+g1*D+g2*D^2+...+gr*D^r in octal format.
void	set_state (const bvec &state)
	Set state (contents in the shift registers) in bvec format.
void	set_state (const ivec &state)
	Set state (contents in the shift registers) in octal format.
bin	shift (void)
	Shift one step and output binary symbol.
bvec	shift (int no_shifts)
	Shift no_shifts steps and output bvec.
int	get_length (void)
	Return length of shift register.
bvec	get_state (void)
	Returns the state of the shift register.

---

Detailed Description

Binary Linear Feedback Shift Register (LFSR).

• The LFSR is on Fibonacci form (see e.g. page 104 in Peterson, Ziemer, and Borth "Introduction to Spread Spctrum communications", Prentice-Hall, 1995.)
• If the connect_polynomial=1+g1*D+g2*D^2+...+gr*D^r is a primitive polynomial a Maximum Length Sequence (m-seq.) of length N=2^r -1 is constructed. Use an arbitrary state not equal to zero, to get a phase of the m-sequence.
• For a table of primtive polynomials see e.g. page 117 in the reference above or a suitable book on coding.

Definition at line 54 of file sequence.h.

---

Constructor & Destructor Documentation

itpp::LFSR::LFSR

(

void

)

[inline]

Constructor.

Definition at line 57 of file sequence.h.

itpp::LFSR::LFSR

(

const bvec &

connections

)

Input connect_polynomial=1+g1*D+g2*D^2+...+gr*D^r in bvec format [g0,g1,...,gr].

Definition at line 39 of file sequence.cpp.

References set_connections().

itpp::LFSR::LFSR

(

const ivec &

connections

)

Input connect_polynomial=1+g1*D+g2*D^2+...+gr*D^r in octal format.

Definition at line 44 of file sequence.cpp.

References set_connections().

---

Member Function Documentation

void itpp::LFSR::set_connections

(

const bvec &

connections

)

Input connect_polynomial=1+g1*D+g2*D^2+...+gr*D^r in bvec format [g0,g1,...,gr].

Definition at line 49 of file sequence.cpp.

Referenced by itpp::Gold::Gold(), and LFSR().

void itpp::LFSR::set_connections

(

const ivec &

connections

)

Input connect_polynomial=1+g1*D+g2*D^2+...+gr*D^r in octal format.

Definition at line 56 of file sequence.cpp.

References itpp::oct2bin().

void itpp::LFSR::set_state

(

const bvec &

state

)

Set state (contents in the shift registers) in bvec format.

Definition at line 64 of file sequence.cpp.

References it_assert.

Referenced by itpp::Gold::set_state().

void itpp::LFSR::set_state

(

const ivec &

state

)

Set state (contents in the shift registers) in octal format.

Definition at line 70 of file sequence.cpp.

References it_assert, and itpp::oct2bin().

bin itpp::LFSR::shift

(

void

)

[inline]

Shift one step and output binary symbol.

Definition at line 122 of file sequence.h.

Referenced by itpp::Gold::get_family(), itpp::Gold::shift(), and shift().

bvec itpp::LFSR::shift

(

int

no_shifts

)

Shift no_shifts steps and output bvec.

Definition at line 77 of file sequence.cpp.

References it_assert, and shift().

int itpp::LFSR::get_length

(

void

)

[inline]

Return length of shift register.

Definition at line 123 of file sequence.h.

Referenced by itpp::Gold::get_family(), and itpp::Gold::Gold().

bvec itpp::LFSR::get_state

(

void

)

[inline]

Returns the state of the shift register.

Definition at line 124 of file sequence.h.

---

The documentation for this class was generated from the following files:

• itpp/comm/sequence.h
• itpp/comm/sequence.cpp

Generated on Wed Apr 18 11:23:42 2007 for IT++ by Doxygen 1.5.2