Patent ID: 7120848

Claim:
A forward error correction (FEC) apparatus used in a transmission system, comprising: a low pass filter (LPF) for passing a low frequency component of an input signal having a predetermined transmission rate; an AC power meter for converting an energy value of an output signal of the LPF into a DC voltage value; a logarithm amplifier for receiving the DC voltage value from the AC power meter, for converting the DC voltage value into a linear DC voltage value, and for outputting the linear DC voltage value to a digital signal processor (DSP); a digital signal processor (DSP) for determining a transmission rate of the input signal according to a magnitude of the DC voltage value and for outputting a control signal for generating a clock signal in response to the determined transmission rate to a clock generator; a clock generator for generating a clock signal in response to the control signal from the DSP and for outputting the clock signal to a forward error correction (FEC) module; and, a forward error correction (FEC) module for performing a FEC operation on the input signal based on the clock signal from the clock generator.