Fig. 2: Non-reciprocal harmonic conversion process.
From: Observation of non-reciprocal harmonic conversion in real sounds
Wave propagation under the designed non-reciprocal isolator, with a pure tone excitation at 400 Hz. Evolution from the input pressure to that below each actively controlled unit cell (PNL, PL1, PL2 below the cell NL, L1, L2, respectively) and then to the final transmitted wave (\({P}_{{{{{{{{\rm{tr}}}}}}}}}\)). Both the frequency spectrum and the time domain profile (insets) are displayed for all pressures in the a forward and the b backward configurations, respectively.
