Information on an elastic rubber string

This paper shows how to use an ideal rubber string, which is clamped down at both ends, as a memory device. The information is stored on the string by giving it an initial shape, where the Fourier coefficients of this shape represent the code bits. Once the string is let go, the wave equation governs the oscillatory movements of the string, but it retains the information in the Fourier coefficients. We show two possibilities to recover this information: analysing a snapshot of the string shape, and analysing its motion at a particular point. Both methods are successful, but for most practical cases the spatial analysis yields a better achievable rate. While the ideal string is used as the intuitive model, our results automatically extend to arbitrary one dimensional wave resonators with clamped down (Dirichlet) boundaries.