Phase-locked web position signal using web fiducials
First Claim
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1. 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 fiducial sensor signals based on the fiducials;
a signal generator configured to generate one or more continuous, periodic movement signals based on movement of the substrate, the movement signals representing an estimated position of the substrate; and
a phase detector configured to determine a phase difference between the fiducial sensor signals and the movement signals and to generate an error signal based on the phase difference, the error signal representing a substrate position error of the estimated position of the substrate.
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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.
81 Citations
11 Claims
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1. A system, comprising:
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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 fiducial sensor signals based on the fiducials; a signal generator configured to generate one or more continuous, periodic movement signals based on movement of the substrate, the movement signals representing an estimated position of the substrate; and a phase detector configured to determine a phase difference between the fiducial sensor signals and the movement signals and to generate an error signal based on the phase difference, the error signal representing a substrate position error of the estimated position of the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system, comprising:
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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; 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; feedback circuitry configured to adjust the movement signals based on the error signal; and
substrate position circuitry configured to determine substrate position along the longitudinal axis based on the adjusted movement sensor signals, wherein;the sensor module is further configured to sense a reference fiducial disposed along the longitudinal axis of the substrate; and
the substrate position circuitry is configured to determine an amplitude of the one or more fiducials based on the reference fiducial.
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Specification