Multi-tone communication system, multi-tone signal demodulation device thereof, and method thereof

A multi-tone communication system, comprising:

• a modulation device comprising:
• a man-machine interface module configured to receive a control command;
• a data processor configured to store at least three pieces of tone data and a first correspondence table, and comprising a calculating unit configured to select at least two of the at least three pieces of tone data according to the first correspondence table, and use the selected at least two pieces of tone data to generate a multi-tone signal corresponding to the control command;
• and
• a speaker module configured to broadcast the multi-tone signal;
• and
• a demodulation device comprising:
• a sound receiving module configured to receive the multi-tone signal;
• a data processor configured to process the multi-tone signal to obtain the pieces of tone data of the multi-tone signal, and determine whether frequency drifts of the pieces of tone data are the same, wherein when the frequency drifts of the pieces of tone data are the same, the data processor decodes the pieces of tone data, to generate an execution command;
• and
• a controller configured to execute the execution command;
• wherein the first correspondence table records a corresponding relationship of the at least three pieces of tone data and a plurality of control commands.