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US 4,786,797 AGranted
Electro-optical data handling system with noise immunity
AssigneeUnisys Corporation
InventorRichard I. Ely
Life of this patent
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Abstract
A source of light modulated by input data provides the modulated light to a phototransistor. A capacitor couples the emitter of the phototransistor to ground. A discharging transistor switch is coupled across the capacitor and a voltage comparator is coupled to the phototransistor emitter for providing a signal when the voltage across the capacitor exceeds a predetermined threshold. A microprocessor coupled to the comparator actuates the discharging switch in accordance with the comparator output.
Claims9
Electro-optical apparatus comprising:
- a source of input data, modulated light means responsive to said input data for providing a modulated light output in accordance with said data,
- a light responsive transistor coupled to receive said modulated light output,
- a capacitor coupled in series circuit with said transistor so that said transistor charges said capacitor in response to said modulated light output impinging thereon,
- whereby a voltage is developed across said capacitor,
- sensing means responsive to said voltage, and
- discharging means coupled across said capacitor for discharging said capacitor,
- thereby providing an electrical output signal in accordance with said data.
4 more elements
Dependencies are inferred from the claim text.