Diffractographic Techniques for Vibration Measurement

The single slit diffraction phenomenon is shown to be useful as a noncontacting vibration measurement technique. The diffracting slit is formed between the vibrating object and stationary reference point. Little or no mass need be added to the object. Several readout techniques are described as well as a method for determining vibratory data along a line, in which case vibratory amplitude may be determined at all points in one coordinate direction.