Patent ID: 7526259

Claim:
A communication system comprising: a radio frequency circuit which includes a radio frequency signal source which produces a radio frequency signal, a power amplifier which power amplifies the radio frequency signal from said radio frequency signal source, and a control unit which controls an output power of the power amplifier; and an antenna which radiates the radio frequency signal output from the power amplifier of said radio frequency circuit; said control unit being configured to hold control data defining a relationship among an operation bias point of said power amplifier and at least two of an input power, and a gain and the output power of said power amplifier, and to adjust the operation bias point of said power amplifier based on the control data such that the output power of said power amplifier is set into a level designated by an external power designating instruction; wherein when the external power designating instruction designates a maximum output power of said power amplifier, said operation bias point is adjusted to a value nearer a class B area than that for the maximum output power within a range that a ratio of an undesired signal component to a desired signal component of the radio frequency signal from said power amplifier is maintained below a distortion reference value specified for a radio communication system, and said control data are referred to for controlling the sum of the input power and the gain of said power amplifier to be equal to the output power of said power amplifier.