Patent ID: 7031094

Claim:
An apparatus to detect a resonance frequency in a system, comprising: an excitation unit exciting the system by increasing a gain of a predetermined frequency band of a driving signal input to the system; a resonance frequency detector frequency-transforming a response signal generated by the system in response to the driving signal input from the excitation unit, and detecting a resonance frequency in a predetermined frequency domain; an excitation signal generator separately generating a first excitation signal with the resonance frequency detected by the resonance frequency detector, and a second excitation signal with a frequency obtained by subtracting the resonance frequency from a sampling frequency selected for frequency transformation; a mixer mixing one of the first excitation signal or the second excitation signal with a driving signal that does not pass through the excitation unit, and inputting a result of combination to the system; a resonance determination unit determining whether resonance occurs in the system using a response signal generated by the system in response to a signal output from the mixer; and a system controller determining a frequency of one of the first excitation signal or the second excitation signal input when resonance occurs in the system, as the resonance frequency.