Digital data communication, i.e. the transmission of discrete encoded information, is already pervasive, but possesses an ever-growing importance for everyday life in contemporary societies. The underlying physics can vary vastly, e.g., between fiber-optic communication and wireless mobile cellular networks. However, at least three unifying elements can clearly be identied, i.e. modulation, transmission and demodulation. Here, we present a setup for demonstrating live as well as teaching the basic elements of data communications. Our setup comprises two identical piezoelectric transducers for actuating and sensing ultrasonic waves on spatially separated plates. The two thin metallic plates, which are bridged by a movable solid piece, constitute the physical transmission medium. Especially the choice of guided
ultrasound waves, which are mechanical waves and equivalent to ordinary sound, should facilitate comprehension by students. In order to further disburden abstraction, the usage of a manifest movable link, which allows for disruption of the data flow, is accompanied by introducing the metaphor of a `drawbridge´. The presented didactic demonstration should be suitable for stimulating the exploration of more advanced topics in the lecture hall, such as source and channel coding, multiple-carrier and multiple-access methods.
Kexel, C.; Mälzer, M. & Moll, J., Connecting Physics to ICT: Demonstrating a `Data Drawbridge’ by means of Guided Ultrasound Waves, European Journal of Physics, 2018 (accepted in July 2018)