Revitalising legacy superheterodyne radios as a teaching resource for amplitude modulation and digital signal analysis

Abstract This paper introduces a low-cost teaching resource that integrates legacy analogue hardware with modern digital tools to support the learning of amplitude modulation (AM) and Fourier analysis in undergraduate physics education. A simple AM transmitter is paired with a legacy superheterodyne receiver and Arduino-based data acquisition, allowing students to probe both RF and audio stages of the receiver. By recording signals, applying fast Fourier transform analysis, and exploring aliasing effects, students connect theoretical principles with observable waveforms. The activity is framed around explicit learning objectives and supported by scaffolding strategies, making it a practical and adaptable resource for instructors seeking to bridge classical radio communication with contemporary digital signal analysis.