Sampling the wavelet

If we put in a time function, we can charactize the wavelength $\lambda$ as it travels through the earth with

$$\lambda={v \over f} ,$$ (2)

where f is the frequency and v is the velocity. In practical terms, this says that our input is a time function that travels in a given interval as a function of the media's velocity, and that different frequencies will travel at different velocities. What is important is that we adequately sample the wavelet. As a result, we can take large depth steps at large velocities and small frequencies. Our migration cost is then generally concentrated at higher frequencies and shallower depths.