Patent ID: 6166840
Filing Date: 2000-12-26
Classification: G06F,H04B

Abstract:
An electronic circuit for receiving and discriminating modulated light of a specific modulation frequency or within a specific modulation frequency range, comprising:a photodiode detector means responsive to light incident to said photodiode detector means for generating an electric current signal in response to said light;a controllable shunting means connected in parallel with said photodiode detector means and controllable between a first operational mode in which said electric current generated by said photodiode detector means is shunted by said shunting means and a second operational mode in which said electric current generated by said photodiode detector means is not shunted by said shunting means; anda control circuit means connected to said photodiode detector means and said controllable shunting means for modulating said controllable shunting means between said first operational mode and said second operational mode, provided said electric current signal generated by said photodiode detector means does not include a signal of said specific modulation frequency or within said specific modulation frequency range, and provided said electric current signal generated by said photodiode detector means includes a signal of said specific modulation frequency or within said specific modulation frequency range, respectively.