Patent ID: 7551527

Claim:
An offset calibration system of a control loop which at least comprises an optical-to-electrical converter, which converts an optical signal to an electrical signal, and an electrical-to-optical converter, which converts an electrical signal to an optical signal, said optical-to-electrical converter generating a pre-output signal and then transmitting said pre-output signal to the electrical-to-optical converter to amplify, said offset calibration system comprising: a comparator for comparing said pre-output signal with a predetermined pre-reference signal to generate a pre-compared signal; an offset calibration module for storing an offset calibration value, which is predetermined and adjustable, for adding to said pre-output signal; and a determination circuit for electrically connecting to said comparator and said offset calibration module, and adjusting said offset calibration value stored in said offset calibration module based on said pre-compared signal generated by said comparator; wherein said determination circuit adjusts said offset calibration value dynamically based on said pre-compared signal, so said offset calibration value can be added to the pre-output signal dynamically to compensate and calibrate the offset of said pre-output signal caused by said optical-to-electrical converter.