APPARATUS AND METHOD FOR GENERATING LOCK SIGNAL IN A QPSK DEMODULATOR

摘要

An apparatus and a method for generating a lock signal are provided to generate an accurate lock signal by considering simultaneously the MSE(Mean Square Error) and the power of an input signal. An apparatus for generating a lock signal includes an error calculating unit, an error comparing unit, a power calculating unit(440), a power comparing unit(450), and a logic device(460). The error calculating unit receives a first signal generated by signal-processing an input signal and calculates MSE. The error comparing unit outputs an error comparing signal of a first logic level if the error value of the MSE calculated in the error calculating unit is less than the reference error value. The power calculating unit(440) receives a second signal generated by signal-processing the input signal and calculates powers. The power comparing unit(450) outputs a power comparing signal of the first logic level if the power value calculated in the power calculating unit is greater than the reference power value. The logic device(460) outputs the lock signal if the logic levels of the error comparing signal and the power comparing signal are all the first logic levels.