Similarly to Ronen 1987, we recast the problem in the frequency domain after applying a log-stretch transform Bolondi et al. (1982). The log-stretch transform makes AMO a time-invariant operator, which means it only depends on the difference between the input and output time. A transformation of the log-stretched data to the Fourier domain is then a convenient way to process the data frequency by frequency. Only at the very end are the time traces reconstructed.