US Patent 7587145 Optical receiver with electric ternary coding

An optical to electrical converter is to receive an incoming optical data communications signal. A binary to ternary encoder has an input coupled to an output of the converter. A ternary to binary decoder has first and second limiting amplifiers, each having a pair of complementary inputs. One of the inputs of each pair is coupled to a first adjustable threshold circuit and the other is coupled to an output of the encoder. A logical summing circuit has a pair of inputs coupled to outputs of the first and second limiting amplifiers, respectively. Other embodiments are also described and claimed.