<matlab> Walsh序列擴頻調制解調的實現
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                                              %
%  函數通過輸入信號序列和函數序號，以及調制解調選擇參數來           %
%  完成擴頻調制解調。original_seq是原始輸入序列，可能是未             %
%  調制序列，也可能是調制序列，walsh_num是walsh函數的序號         %
%  select選擇對輸入的序列進行調制還是解調。                                 %
%                                                                                              %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function [sequence] = DS_walsh_modulation_demodulation(original_seq,walsh_num,select)
if nargin < 2                                       
    error('輸入參數不足!');
end
if length(original_seq) < 1
    error('原序列輸入錯誤，無法進行擴頻調制！');
end
walsh_sequence = walsh_sequence_generator(64);
walsh_seq = walsh_sequence(walsh_num+1,:);
or_len = length(original_seq);
len = length(walsh_seq);
if select == 1                                      % 進行擴頻調制
    mo_seq = walsh_seq.'*original_seq;
    sequence = reshape(mo_seq,1,len*or_len);
else                                                   % 進行擴頻序列的解調操作
    de_seq = reshape(original_seq,len,or_len/len);
    sequence = walsh_seq*de_seq/len;
end