Although the steps in FIG. 6 are described to be sequentially performed, they merely instantiate the technical idea of some embodiments of the present disclosure. Therefore, a person having ordinary skill in the pertinent art could appreciate that various modifications, additions, and substitutions are possible by changing the sequences described in the drawing or by performing two or more of the steps in parallel, without departing from the gist and the nature of the embodiments of the present disclosure, and hence the steps in FIG. 6 are not limited to the illustrated chronological sequences.

As described above, the calibration method of the power amplifier performance shown in FIG. 6 can be implemented as a program and recorded in a computer-readable recording medium such as CD-ROM, RAM, ROM, memory card, hard disk, magneto-optical disk, storage device, etc.

FIG. 7 is a diagram illustrating output characteristics of a power amplifier by combination in the input signal according to some embodiments of the present disclosure.

As shown in FIG. 7, where the demodulated signal source is a combination of multiple carriers, the respective carrier frequencies may be combined in various forms within the available frequency range. This means that the power amplifier 140 has different output characteristics depending on how the carrier frequencies of the signal source are combined.