Bar-coded data input terminals
Patent 4196845 Issued on April 8, 1980. Estimated Expiration Date: 
April 10, 1998. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
April 10, 1998. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3699312 3792236 3918029 Hand-operated scanner Bar code scanner Patent #: 3991299 InventorAssigneeApplicationNo. 05/895074 filed on 04/10/1978US Classes:235/462.27, Analog to square wave converter (e.g., digitizer, binarizer, slicer)235/455, Light level control235/462.49, Wand-type reader (e.g., manual scan)235/482, Hand feed250/555Including coded recordExaminersPrimary: Cook, Daryl W.Attorney, Agent or FirmInternational ClassesG06K 19/00 (20060101)G06K 7/10 (20060101) Foreign Application Priority Data1977-04-15 GBAbstractSignal processing circuitry for a bar-coded data input terminal having a bar-code reading device, such as light pen, for reading bar-coded identity data, from bar-coded identity labels, attached to items to be identified for instance takes an output signal from the reading device and derives a processed signal in which changes of signal level are cleaner than corresponding level changes in the output signal. The signal processing circuitry employs a high gain operational amplifier to an input of which the output signal is passed through a capacitor. The amplifier has a capacitor and two diodes, with their conduction directions opposite, connected in parallel between the input and the output of the amplifier, from which an amplified signal opposite to the reading device output signal is delivered. A threshold detector receives the amplified signal and provides a processed signal in which signal level changes in dependence upon the amplified signal passing through threshold levels.Other References
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