function N_char = Watermark_characters(N_host)
% Determine the number of characters that can be embedded in the host signal
%
% INPUT:  N_host - The length of the host signal to be watermarked
% OUTPUT: N_char - The number of characters that can be embedded

% Common variables
Common_para;

% The number of watermark bits that could be embedded
N        = N_host;                  % The length of the host signal
Nt_block = fix(N/block_size);       % The total number of blocks 
N_wm     = Nt_block * N_bit;        % The length of original watermark

N_char = fix(N_wm / letter_size); % The maximum number of characters 

