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Method and apparatus for downloading information from a controllable light source to a portable information device

  • US 5,488,571 A
  • Filed: 11/22/1993
  • Issued: 01/30/1996
  • Est. Priority Date: 11/22/1993
  • Status: Expired due to Fees
First Claim
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1. A portable information device for receiving data from a data transmitter of the type having a CRT video display providing raster scanning of a screen at a horizontal scanning frequency and a vertical frame rate;

  • and transmitting binary coded data in blocks of serial data bits as light pulses at a preselected pulse repetition rate less than said horizontal scanning frequency and greater than said vertical frame rate in synchronism with raster scanning of said screen so as to provide an integral number of one or more blocks for each vertical frame, said portable information device comprising;

    (a) a portable casing adapted to be manipulated at a location spaced from, and within line of sight of, said screen;

    (b) a photosensor mounted on said casing adapted to detect said light pulses when said portable casing is manipulated to direct said photosensor toward said screen;

    (c) amplifier means within said casing connected to said photosensor to provide amplified binary coded receiver pulses corresponding to said light pulses,(d) filter means within said casing connected to said amplifier means and adapted to pass signals at said preselected pulse repetition rate and to attenuate ambient artificial light frequencies;

    (e) first means connected to receive said receiver pulses from said filter means and to provide binary coded data blocks adapted to vary between high and low logic levels at said preselected pulse repetition rate; and

    (f) asynchronous data collection means within said casing connected to said first means.

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