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AssigneeInternational Business Machines Corporation
InventorsEric C. Broockman, Robert T. Cato, George J. Laurer
Estimating the term…
A fixed position optical scanner with a multi-faceted holographic disk includes circuitry for adjusting the lockout voltage as a function of the focal length of the active facet. The disk position is tracked to identify the active facet. A facet identifying signal is used to address a lockout table in processor memory. A digital value retrieved from the lockout table is converted to analog form and applied through a resistor to a voltage divider in the threshold circuit. The voltage divider scales down a white peak following voltage and compares it to a black peak following voltage. The facet-dependent lockout voltage biases the junction of the voltage divider to vary the effective lockout voltage as a function of the focal length of the currently active facet.
For use in an optical scanner of the type having a coherent light beam source, a multifaceted rotating holographic optical element for deflecting the coherent light beam along predetermined scan lines, a photosensitive detector for generating data signals and peak follower circuits for producing first and second peak voltages dependent upon the maximum and minimum values of the data signals produced by the photosensitive detector, an improved lockout circuit for permitting the output of only those signals which exceed the second peak voltage by a predetermined value, said lockout circuit including:
For use in an optical scanner of the type having a coherent light beam source, a multifaceted rotating holographic optical element for deflecting the coherent light beam along predetermined scan lines, a photosensitive detector for generating data signals and means for generating a lockout voltage for inhibiting the transfer of data signals if the maximum and minimum values of data signals have less than a predetermined separation, the improvement comprising means for adjusting the lockout voltage as a function of the properties of the currently active facet of the multifaceted rotating holographic optical element.
Dependencies are inferred from the claim text.