TABLE OF CONTENTS The term average power is used to specify almost all RF and wireless SOC devices. The terms pulse power and modulated power will be discussed later.
Power meters are inherently slow and are therefore not widely used in production-test solutions to measure RF power. If a power meter is not used to measure RF power, but instead the RF signal is downconverted to an IF signal, and then the IF signal is digitized across some known resistor, R, the discussion of RF power is reduced to the block diagram shown in Figure 4.2.
In basic electrical theory, power is said to be the product of voltage and current. But for ac voltage cycles, the product V I varies during the cycle. This is shown by the P curve. Notice that the P curve varies by twice the frequency (2 f) of the voltage cycle. The P curve has both a dc component and an ac component. When referring to power, this most commonly refers to the dc component of the power product and not the ac component.
As was mentioned earlier, the fundamental definition of power is energy per unit time. This is in agreement with the definition of a watt as energy transfer at the rate of one joule per second. When looking at the P curve, we are suddenly faced with a question. Over what time is the energy...
