Phase as a function of f. The phase (in cycles) of the extremal function h as a function of frequency at the distance to the stapes. The solid line is the phase as determined by the extremal function. The dashed line is the physiologically correct substitute at low frequencies. Note that the phase values in this region are practically irrelevant for signal processing, because the amplitude values in this region are negligible. Under the tonotopic axis d corresponds to the frequency . The parameters are the same as in Figure 2.