RECEIVED SIGNAL STRENGTH MEASURING APPARATUS, RECEIVED SIGNAL STRENGTH MEASURING METHOD, RECORDING MEDIUM, AND KEYLESS ENTRY SYSTEM

摘要

A signal strength obtaining unit obtains, first received signal strengths at a receiver over a first period of time in which a target signal is transmitted, and obtains second signal strengths at the receiver over a second period of time in which the target signal is not transmitted. A signal strength calculating unit calculates a signal strength of the received target signal by using a first method based on an assumption that a noise signal whose amplitude changes is superimposed on the target signal when a variance value of the second signal strengths exceeds a first threshold, and calculates the signal strength of the received target signal by using a second method based on an assumption that a noise signal whose amplitude is constant is superimposed on the target signal when the variance value of the second signal strengths is less than or equal to the first threshold.