Phase-locked web position signal using web fiducials
Assignee3M Innovative Properties Company
InventorsDaniel T. Theis, Daniel H. Carlson, Brian K. Nelson
Life of this patent
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Abstract
Approaches for enhancing web position determination involve phase locking a web movement encoder signal to a sensed web fiducial signal. Fiducials disposed along a longitudinal axis of a substrate are sensed and corresponding sensor signals are generated. An estimated web position is provided by one or more encoder signals. The phase difference between the sensor signals and the encoder signals is calculated and the web position error is determined based on the phase difference. The web position error signal can be fed back to adjust the encoder signals which improves the accuracy of the web position determination.
Claims11
A system, comprising:
- a sensor module configured to sense one or more fiducials disposed along a longitudinal axis of a substrate and to generate one or more continuous, periodic sensor signals based on the fiducials;
- a signal generator configured to generate one or more continuous, periodic signals based on movement of the substrate;
- and
- a phase detector configured to determine a phase difference between the sensor signals and the movement signals and to generate an error signal based on the phase difference.
Dependencies are inferred from the claim text.