This module begins by considering the fundamental limitation of continuous wave transmission. The fact that we must use pulses to achieve depth resolution forces a discussion about a whole new group of timing considerations and issues, referred to as the pulse wave parameters. This discussion about PW timing and pulse characteristics becomes the foundation for understanding depth resolution, the point at which aliasing occurs, the calculation of the frame time and the frame rate, as well as temporal resolution. Additionally, in this module, we learn how the pulse duration affects the bandwidth and we learn about the benefits of broadband transducers.