Transfer of chaotic masked audio signal by FDM method

In this thesis, the MATLAB simulation of a secure communication system is realized by transmitting the masked audio signal with the help of a chaotic signal and a second chaotic signal used to remove the mask on the receiving side on a single channel and by removing the mask on the receiving side. For this purpose, the frequency division multiplexing (FDM) method was used to transmit Sprott chaotic oscillator data from a single channel to obtain chaotic signals. Double sideband amplitude modulation is used to transmit signals in FDM method. PID and PD control methods for the synchronization of chaotic signals on the receiver side were compared. The signal consisting of the sum of the message and synchronization signals transmitted from a single channel by the FDM method was separated using Bandpass 8th Degree Butterworth filters. In order to find the difference between input and output signals, mean square error (HKO) method was used. As a result of the study, it was observed that the PD method for synchronization of chaotic signals was lower than the PID of the HKO. In addition, the HKO of the audio signal at the input and output was observed to be lower with the PD controller and was calculated to be 0.098. The audio signal obtained at the output was passed through a bandpass filter to reduce the error and the HKO was found to be 0.037. It has been found that in the simulation environment, the system can mask an audio signal and transmit it over a single channel and unmask the receiver by intelligently reaching the original audio signal. Keywords: DSB-AM, FDM, Secure communication, PID, Sprott chaotic oscillator