Digital Waveguide Definition

• A digital waveguide is defined as a ``bidirectional delay line'' associated with a (real) wave impedance $R>0$

• A digital waveguide simulates ideal wave propagation (lossless, non-dispersive) exactly for frequencies $f$ below the Nyquist limit $f_s/2$

• We'll derive $R$ from first principles later on
  (for ideal strings)