A CDMA acoustic communication system for multiuser based on sound card

In this paper, a CDMA acoustic communication system for multiuser based on hardware platform is developed. The sound card in the computer with sound box and microphone is used as the energy transduction to accomplish acoustic communication. For the hardware part, DS18B20 is taken for example as the data source to generate the original signals and MAX232 chip is adopted to connect the MCU to the RS-232 port in the computer. For the software part, MATLAB is used to accomplish reading and writing of the serial port data and carry out algorithms such as spread spectrum and modulation based on QPSK-CDMA (Quadrature Phase Shift Keying-Code Division Multiple Access). MMVARI is adopted to drive the sound card to form the acoustic signals from the digital data. The experimental results indicate good quality of the communication system.