| 摘要 |
Apparatus is disclosed for measuring the movement of an object comprising an optical imaging device for producing an image of said object, a grating structure positioned to receive the image of said object produced by said imaging device, drive means for producing a periodic relative movement between said grating structure and the image formed thereon, means for generating reference signals corresponding to said periodic relative movement, photoelectric receiving means positioned for receiving light from said grating structure corresponding to the image thereon, said photoelectric receiving means producing electrical rotating field signals, a control circuit connected for receiving said reference signals and said electrical rotating field signals for producing control signals indicative of the movement of said object with respect to a direction of movement at least approximately parallel to said relative movement, and a bidirectional counter connected to receive said control signals for indicating the movement of said object. A method for measuring object movement is also disclosed.
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