Abstract: A system to determine unwanted noise produced by simulation equipment. In one embodiment, an angular rotation noise measuring system comprises a stable body, a laser, at least one interferometer and at least one mirror. The laser is adapted to generate a primary laser beam and is mounted to the stable body. The at least one interferometer is adapted to split the primary laser beam into two or more out of phase secondary laser beams. Moreover, the interferometer is coupled to the stable body. The at least one mirror is coupled to a fixture on a vibration generating device. The fixture is adapted to hold a device under test. Each mirror is adapted to reflect an associated secondary laser beam back to the interferometer such that an interference pattern is formed with the secondary laser beams. Changes to the interference pattern determine the angular rotation noise caused by the vibration generating device.

Abstract: The present invention provides devices and methods for indicating or gauging the position of one or more holes in a workpiece. In one aspect of the present invention reusable devices that can be removably engaged with a bore or tapped hole in a workpiece for accurately indicating the center axis of the bore or tapped hole are provided. An exemplary device in accordance with the present invention includes an expandable shank, indicating surface, and driving head. The driving head can be used to install the device into a hole in a workpiece. The expandable shank can be expanded to positively engage the device with the hole in the workpiece and the indicating surface can be referenced, with a probe, to determine the center axis of the hole in the workpiece.