Transmission of digital information over cell phone audio channels

摘要

This project was designed to assess the viability of transmitting data over cell phone audio channels through the use of vowel-like sounds. Sound data was generated by using LPC to generate signals with bandwidth and resonant frequencies corresponding to known formants. Modifications were made to the pulse train and formant frequencies to improve detection performance. A filter bank was also implemented to balance the magnitudes of the frequencies for the symbol set. These symbols were transmitted over a pair of connected cell phones and processed using the Goertzel algorithm. The experiments were carried out over one set of cell phones and repeated multiple times in the same conditions to ensure accuracy. The final system determined that all 10 of the formants tested were potential symbols. Future work should be dedicated to automating detection and determining a transmission rate for the system.