This PTM begins with a problem that requires a solution. Shown here is a block diagram of a typical wireless transmitter that incorporates measurement and control of RF power. Using a directional coupler that is close to the antenna, a small portion of the signal from the high powered amplifier is coupled off and fed to an RF detector. The voltage output of the RF detector is then applied to an analog-to-digital converter (ADC) to be digitized. Using the code from the ADC, the RF power being transmitted is calculated. This power reading is compared to a setpoint power level in the microcontroller or DSP. If any discrepancy between setpoint and the measured power exists, a power adjustment is made. This power adjustment can be made in a number of ways: the amplitude of the baseband data driving the radio can be adjusted, the gain of a a variable-gain amplifier can be adjusted or the gain of the High Power Amplifier (HPA) can be changed. In this way, the loop regulates itself and keeps the transmitted power within desired limits.