| 摘要 |
An apparatus and method for synchronizing to a scanning galvanometer system provide for magnification changes on the order of one part in a thousand. The apparatus employs two phase locked loops connected in series with a digital counter divider. The combination of phase locked loop, digital divider, and phase locked loop provide a multiplication factor equal to a*c/b which enables the required precision in magnification step change to be achieved. Critical to operation of the circuitry is the provision for resetting the divider counter when the first phase locked loop is sufficiently synchronized to a ruled grating which is part of the scanning system.
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