US Patent 7549340 Apparatus for measuring vibration characteristic of head gimbal assembly

An apparatus surely measures the vibration characteristic of a head gimbal assembly and has a wide range of resonance frequencies to be set, the apparatus has a first laser Doppler vibrometer to detect a vibration velocity of a shaker, a second laser Doppler vibrometer to detect a vibration velocity of a head of the head gimbal assembly fixed to a fixture, and a reflection mirror to orthogonally reflect a laser beam emitted from the first laser Doppler vibrometer toward the fixture fixed to the shaker, and the apparatus finds the vibration characteristic of the head gimbal assembly according to the detected vibration velocities.