Patent ID: 7366257
Filing Date: 2008-04-29
Classification: H04L

Abstract:
1. A carrier recovery device of a digital television (TV) receiver comprising: an analog/digital (A/D) converter converting an analog signal to a digital signal by using a fixed frequency; a phase splitter splitting the digital signal to a real signal and a quadrature signal; a first complex multiplier outputting a real base band signal i(t) and a quadrature base band signal q(t) by performing a complex multiplying of the real and quadrature signals of a split passband of the phase splitter and a first complex carrier outputted from a first numerically controlled oscillator (NCO); a second complex multiplier outputting Like Offset Quadrature Amplitude Modulation (QAM) signals i′(t) and q′(t) by performing a complex multiplying of the real and quadrature base band signals i(t) and q(t) and a second complex carrier outputted from a second NCO; first and second squarers receiving the Like Offset QAM signals i′(t) and q′(t), and performing a nonlinear operation; a subtractor receiving output signals from the first and second squarers, and performing a subtraction operation; a passband filter extracting components corresponding to a carrier frequency from the signals outputted from the subtractor; a Gardner phase error detector detecting a phase error between the filtered signal of the passband filter and a particular multiple of a fixed frequency; and a loop filter low-pass filtering the phase error, and outputting the filtered phase error to the first NCO.