For Advanced Digital Communication Systems (ADCS) to function efficiently, Radio Frequency Power Amplifiers (RFPA) in the ADCSs have to function with linearity. It is noted that a process of causing the RFPA to function with linearity is hereafter referred to as linearizing the RFPA. An RFPA comprises one or more transistors. As a result, operational aspects of the RFPA and linearity corresponds to operating points of the one or more transistors. An operating point of a transistor is indicative of an operational characteristic of the transistor. The operating point of the transistor depends on a bias signal received at the transistor. Axiomatically, the operating points of the one or more transistors depend on one or more bias signals received at the one or more transistors.
Optimum operating points are the operating points of the one or more transistors corresponding to occurrence of linearity in functioning of the RFPA. Hence, when the operating points of the one or more transistors match the optimum operating points, the RFPA functions with linearity. Moreover, when the one or more transistors are biased to the optimum operating points, the RFPA causes reduced third order Intermodulation Distortion (IM3). In order to linearize the RFPA, typical systems adjust the one or more bias signals to bias the one or more transistors to the optimum operating points.
However, the optimum operating points vary with variations in multiple factors. For example, the optimum operating points vary with variations in ambient temperature of the RFPA. Further, rate of the variations in the optimum operating points depend on a process corner of the one or more transistors in the RFPAs. Hence, while adjusting the one or more bias signals, the process corner and the variations in the ambient temperature have to be accounted for.
The typical systems adjust the one or more bias signals to compensate for variations in the ambient temperature and consequently, maintain the one or more transistors at the optimum operating points. However, the typical systems fail to take the process corner into account while adjusting the one or more bias signals. As discussed earlier, the rate of the variation in the optimum operating points depend on the process corner. Hence, the typical systems fail to compensate the one or more bias signals accurately. As a result, the typical systems fail to maintain the one or more transistors at the optimum operating points in an event of a variation in the ambient temperature. Hence, the typical systems fail to linearize the RFPA.
USPTO Backgrounds
USPTO Backgrounds