There is once a function called 'mlbs' in Matlab but no longer included. The
description of it can be found at
http://dali.feld.cvut.cz/ucebna/matlab/toolbox/fdident/mlbs.html
The contributed function is a mimic of the 'mlbs' function.
Now only LFSR lengths of 2 to 32 are supported. However, further support up to
length of 168 can be added. Please refer to
http://www.xilinx.com/support/documentation/application_notes/xapp052.pdf
mlbs
Generate maximum length binary sequence (pseudo-random binary sequence).
Syntax
bitseries = mlbs(log2N)
[bitseries,nextstnum] = mlbs(log2N,bitno,startnum)
Description
mlbs generates a maximum length binary sequence (column vector bitseries),
using
a shift register of length log2N. The minimum value of the argument log2N is 2,
the maximum value is 30. The length of the generated sequence is given by
bitno,
that is, a partial sequence can also be generated. The default value of bitno
is
2^log2N-1, that is, the full length of the PRBS with the given register length.
The generation is based on a binary shift register with modulo 2 feedback. The
starting value of the register is startnum. The register contents can be
obtained via nextstnum, which can be used for the continuation of the sequence
generation.
Default Argument Values
bitno = 2^log2N-1, startnum = 2^log2N-1
Examples
bitseries = mlbs(10); %Length: N = 1023 = 2^10-1
Diagnostics
The register length must be an integer number between the allowed minimum and
maximum, otherwise an error message is sent:
log2N is not integer
or
log2N = ... is not allowed
startnum must be between 1 and 2log2N-1, otherwise the error message is
startnum out of range
Algorithm
The feedback shift register is implemented in a MATLAB vector, according to the
definition (see [1]).
See Also
dibs
References
[1] K. R. Godfrey, ed.: Perturbation Signals for System Identification.
Englewood Cliffs, Prentice-Hall, 1993.
