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. Author manuscript; available in PMC: 2010 Mar 5.
Published in final edited form as: Ultrasound Med Biol. 2007 Apr;33(4):620–629. doi: 10.1016/j.ultrasmedbio.2006.10.008

Figure 3.

Figure 3

Results of simulations illustrating the impact of having an initial (nonzero) second harmonic component (14 MHz), for both water (1.00 gm/cm3 mass density, 1480 m/s speed of sound, 5.0 nonlinear B/A parameter, and frequency dependence of attenuation proportional to square of the frequency) and isopropanol (see Fig 1 caption for assumed material parameters). (a) Results from the simulation showing the power in the fundamental and second harmonic as a function of axial distance. The case of no initial second harmonic is compared with the case where a small (-60 dB re:1f) initial second harmonic component is present. (b) The ratio Φ, when a small initial second harmonic component is present illustrating extrapolation errors in the regime of small axial distance.