Patent ID: 7574146

Claim:
An optical communication node, comprising: a photodetector configured to receive the optical signal and convert the optical signal into an electrical signal; a clock and data recovery circuit coupled to the photodetector, the clock and data recovery circuit having an associated threshold voltage, the clock and data recovery circuit comparing the electrical signal to the threshold voltage to thereby generate a plurality of bits; a first circuit coupled to the clock and data recovery circuit, the first circuit including a decoder configured to change selected bits of the plurality of bits to thereby generate corrected bits, the first circuit being configured to output a plurality of bit patterns, each of the plurality of bit patterns including a corresponding one of the plurality of bits and a corresponding one of the corrected bits; and a second circuit, wherein each of first ones of the plurality of bit patterns has a corresponding one of a first group of the corrected bits, and each of second ones of the plurality of bit patterns has a corresponding one of a second group of the corrected bits, each of the first group of the corrected bits having a first value and each of the second group of the corrected bits having a second value, the second circuit being configured to count a first number of the first ones of the plurality of bit patterns and a second number of the second ones of the plurality of bit patterns, such that if the first number is greater than the second number and a sum of the first and second numbers exceeds a predetermined value during a predetermined time period, the threshold voltage is incremented by a predetermined voltage.