Radar systems radiate each pulse at the carrier frequency during transmit time, wait for returning
echoes during listening or rest time, and then radiate a second pulse, as shown in figure 1-3. The number
of pulses radiated in one second is called the pulse-repetition frequency (prf), or the pulse-repetition rate
(prr). The time between the beginning of one pulse and the start of the next pulse is called PULSEREPETITION
TIME (prt) and is equal to the reciprocal of prf as follows: