Patent ID: 7654145

Claim:
A method of measuring vibration in a bladed rotor structure with a vibration monitor, said bladed rotor structure comprising a plurality of blades supported on a rotor for rotation about a rotor axis, and said vibration monitor comprising a stationary sensor positioned at a peripheral edge of said bladed rotor structure and a plurality of sensor targets positioned at circumferentially spaced locations on said bladed rotor structure, comprising the steps of: providing at least one sensor for sensing passage of said sensor targets; providing an excitation structure adjacent to said rotor structure for providing an excitation force to said blades; rotating said rotor structure about said rotor axis at a first speed; causing said excitation structure to move in a circular path about said rotor axis at a second speed; and sensing target passing events caused by said sensor targets passing said at least one sensor to provide a time-dependent output signal responsive to passage of each said sensor target to said vibration monitor.