Audio Modem
For the final project in my Analog and Digital Comms. class, two friends and I implemented an audio modem using Binary Phase Shift Keying (BPSK) for Line of Sight transmission in a room.
Access our full paper here.
Block Diagram for the Audio Modem
Our Setup
Data was sent through Edifier E10 speaker system that has a flat frequency response up to 10 kHz. Transmitted carrier wave frequency (at 5 kHz) fell well-within this range. A Blue Yeti mic placed at the other end of the room acted as the receiver. The received audio signal was sampled at 44.1kHz in Audacity software and this data was then processed in MATLAB.
Side by side comparison of received and transmitted image
