Author: Herb Estrada ~ Chief Engineer , Cameron Measurements
From : http://www.c-a-m.com/Forms/Product.aspx?prodID=8d75e4a4-d49c-43dd-8738-5776276254d1
A time-of-flight ultrasonic flow measurement system projects acoustic energy along one or more diagonal paths through the pipe in which flow is to be measured. Such an acoustic path is illustrated in Figure 1. If the upstream or A transducer is excited by a burst of electrical energy, it will transmit a packet or pulse of acoustic energy into the adjacent medium.