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US 2004/0165682 A1Published application
Carrier recovery device of digital TV receiver
AssigneeLG Electronics Inc.
InventorJung Sig Jun
Life of this patent
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Abstract
A carrier recovery device of a digital TV receiver is disclosed, which can stand a multiple path noise. In the carrier recovery device, it is possible to recover a carrier with a phase error component of the carrier existing on data blocks as well as a carrier signal, whereby it has the carrier recovery function even in case a carrier recovery unit is not operated properly.
Claims15
A carrier recovery device of a digital TV receiver comprising:
- an 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 the split passband and a first complex carrier outputted from a first NCO;
- a second complex multiplier outputting Like Offset 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;
- a phase error detector detecting a phase error to a particular multiple of a fixed frequency on basis of the Like Offset QAM signals i′(t) and q′(t);
- and
- a Loop filter low-pass filtering the phase error, and outputting the filtered phase error to the first NCO.
4 more elements
A carrier recovery device comprising:
- an A/D converter converting an analog passband signal to a digital passband signal by using a fixed frequency;
- a phase splitter splitting the digital passband signal in 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 the split passband and a first complex carrier outputted from a first NCO (Numerically Controlled Oscillator);
- a second complex multiplier outputting Like Offset 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 the signals outputted from the first and second squarers, and performing a subtract 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 and a particular multiple of a fixed frequency;
- and
- a Loop filter low-pass filtering and outputting the phase error to the first NCO for carrier recovery.
7 more elements
A carrier recovery device comprising:
- an A/D converter converting an analog passband signal to a digital passband signal by using a fixed frequency;
- a phase splitter splitting the digital passband signal in 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 the split passband and a first complex carrier outputted from a first NCO (Numerically Controlled Oscillator);
- a second complex multiplier outputting Like Offset 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 absolute value calculators receiving the Like Offset QAM signals, i′(t) and q′(t), and calculating absolute values thereof;
- a subtractor receiving the outputs of the first and second absolute value calculators, and performing a subtract operation;
- a passband filter receiving the signals from the subtractor, and extracting components corresponding to a carrier frequency therefrom;
- a Gardner phase error detector detecting a phase error between the filtered signal and a particular multiple of a fixed frequency;
- and
- a Loop filter low-pass filtering and outputting the phase error to the first NCO for carrier recovery.
7 more elements
Dependencies are inferred from the claim text.