Patent Number: 6,166,840

Title: Electronic circuit for receiving and discriminating modulated light and an electronic price display comprising said circuit

Abstract: An electronic circuit (50) for receiving and discriminating modulated light of a specific modulation frequency or within a specific modulation frequency range includes a photodiode detector (52) responsive to light incident thereto for generating an electric current signal. A controllable shunt (54) is connected in parallel with the photodiode detector (52) and is controllable between a first operational mode in which the current is shunted, and a second operational mode in which the current is not shunted. A control circuit (56) is connected to the photodiode detector (52) and the shunt (54) for controlling the controllable shunt (54) into (a) the first operational mode, provided that the current signal does not include a signal of the specific modulation frequency or within the specific modulation frequency range, or (b) the second operational mode, provided that the current signal includes a signal of the specific modulation frequency or within the specific modulation frequency range.

Inventors: Barfod; Jesper (Dronningmoelle, DK)

Assignee: Esel-Krabbe Systems A/S

International Classification: G06F 3/147 (20060101); H04B 10/158 (20060101); H04B 10/10 (20060101); H04B 10/152 (20060101); H04B 010/06 ()

Expiration Date: 12/26/2017