Patent ID: 7394996

Claim:
A system comprising: an optical receiver for receiving optical signals and for converting the optical signals into electrical signals; a transimpedance amplifier for filtering the electrical signals; a limiting amplifier having a first input coupled to the transimpedance amplifier; and an automatic threshold control coupled with the transimpedance amplifier, the automatic threshold control providing a reference voltage to a second input of the limiting amplifier; wherein the automatic threshold control comprises a common emitter portion and an emitter follower portion, the common emitter portion including a capacitor coupled to the emitter follower portion, the capacitor thereby coupled to be charged by the electrical signals; a switch control coupled to an output of the emitter follower portion and to the second input of the limiting amplifier, the switch control being adapted to turn the limiting amplifier on and off in response to whether or not the electrical signals are being received; and wherein logic high signals and logic low signals in the electrical signals are determined relative to the reference voltage.