# how to perform FFT on multivalued bit string?

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Jyothi Alugolu on 27 Mar 2017
Answered: Walter Roberson on 27 Mar 2017
hi,
i have a bit string of size 560*1 of values 0 and 1 and some cells contains both 0 and 1 values.. now, i need to apply FFT on this bit string.. to do so, first i need to convert cell values to double values by making use of Cell2mat function (bcz FFT function can be applied on double values only).. so, i used cell2mat function and i applied fft on it... i got wrong results... i.e., if a cell in bit string contains [0,1] ,then after using cell2mat function the values 0 and 1 are being splitted and size of bit string is being increased...
code for binary string :
new_len = 576;
old_len = length(a);
mapped_index = 1 + mod((1:old_len) - 1, new_len);
b = accumarray( mapped_index(:), a(:), [new_len 1], @(L) {unique(L.')} ) .';
B1=cell2mat(b);
b2=B1';
i got error: undefined function fft for input arguments of type cell...
Can anyone help me with this..

Walter Roberson on 27 Mar 2017
"Can anyone help me with this.."
No. There is no defined meaning for taking the fft of a many-to-one mapping.
Taking the Discrete Fourier Transform (fft) of a bit-string is questionable itself.