Device for checking positional accuracy

摘要

A device for checking positional accuracy is disclosed which precisely checks the accuracy of the mounting position of a plurality of magnetic heads mounted on a rotary disk along the edge thereof. The device includes a laser which projects a laser beam in a direction at a predetermined angle with respect to the rotary disk. The laser beam is successively scattered by head gaps of the magnetic heads. A photosensor converts the scattered light components into photoelectric signals each containing two photoelectric signal components. The two photoelectric signal components of each of the photoelectric signals are differentially amplified by an operational amplifier. The operational amplifier produces successive differential signals which are supplied to a zero-crossing detector. The accuracy of the mounting position of the magnetic heads is then checked based on the interval between adjacent detected zero crossings.