1-8system. The figure is drawn just to show you how average power is calculated.) Pulse-repetition time isused to help figure average power because it defines the total time from the beginning of one pulse to thebeginning of the next pulse. Average power is figured as follows:Figure 1-5.—Pulse energy content.Because 1/prt is equal to prf, the formula may be written as follows:The product of pulse width (pw) and pulse-repetition frequency (prf) in the above formula is calledthe DUTY CYCLE of a radar system. The duty cycle is a ratio of the time on to the time off of thetransmitter, as shown in figure 1-6. The duty cycle is used to calculate both the peak power and averagepower of a radar system. The formula for duty cycle is shown below:NOTE: Pulse repetition frequency (prf) and pulse repetition rate (prr) are interchangeable terms.