Acoustic Transmitter

The Acoustic Transmitter app is designed for use with hands-on guided learning explorations in digital communication and signal processing.  A guided course of study is available at iTunesU [https://go.osu.edu/commlab] and Mathworks Matlab Courseware [http://www.mathworks.com/academia/courseware/]. The app provides a digital communication transmission signal modulated to an acoustic carrier frequency.

The Acoustic Transmitter app can be operated in two modes: carrier tone and text transmission.  In either case, the sampling rate to convert from a digital signal to an acoustic signal is 44.1 kHz. In carrier tone mode, the app simply transmits the waveform cos(2πfct) for a 400 millisecond duration at a user-specified carrier frequency. The user can specify any carrier frequency to explore the effects of sampling and aliasing. In the text transmission mode, the app provides a digital communication transmission modulated to a programmable acoustic carrier frequency. The transmitter implements BPSK or QPSK data modulation, user-specified pulse shaping and symbol rate, a choice of pilot symbols for synchronization, and a data payload fixed at 50 ASCII characters. A user input with fewer than 50 characters is padded with underscores to be 50 characters in length and a longer input is truncated to 50 characters.

This app is not currently available in other languages.