Answer to Question #62142 in MatLAB | Mathematica | MathCAD | Maple for Linda

Question

Write a matlab function nybblise which takes as input digital signal of 0’s and 1’s stored in a vector of size N ×1, and breaks it into four 4-bit nybbles, which are returned as the columns of a 4×N/4 matrix.
Your function must return -1 if the N is not a multiple of 4.
Following is the signature of the function.
function A = nybblise(d)
Input: d - digital signal as a vector of size N x 1
Output: A - nybbles as a 4 x N/4 matrix OR -1 if N is not a multiple of 4
Note: This function must use loops rather than MATLAB built-in functions such as reshape, fliplr, flipud.

Answer 1

% nybblise.m
function A = nybblise(d)
% First index is used to calculate how many multiples of 4 (thus number of columns) it takes to get
% 'd' given 'd' is a multiple of 4 to begin with.
index = 0;
% Second index is used to for a loop where a zero matrix of size 4*N (where
% N = number of columns needed which is the value of 'index') in which the
% values of 'd' replace the zero matrix to output A with a 4*N matrix with the values of 'd'.
index2 = 0;
% d_mul is first set to the length of input 'd' and is used later to find
% the number of columns needed for our output using 'index'
d_mul = length(d);
%
while d_mul > 0
d_mul = d_mul - 4;
index = index + 1;
end
matrix = zeros(4,index);
if d_mul == 0
while index2 <= (index-1)
matrix(:,(index2+1)) = d([(index2*4+1) (index2*4+2) (index2*4+3) (index2*4+4)]);
index2 = index2+1;
end
A = matrix;
else
A = -1;
end
end