| 摘要 |
PURPOSE:To compensate a DC drift of a delay detection circuit automatically and quickly by detecting an error signal between an output signal after delay detection and a desired signal and using a drift estimate circuit to cancel the correlation between the error signal and an input signal to the delay detection circuit so as to implement drift compensation. CONSTITUTION:An output signal from a quasi-synchronization detection circuit is inputted to a base band processing delay detection circuit from an input terminal 37 via a DC amplifier. After the input signal from the input terminal 37 is inputted to a DC drift compensation circuit comprising a full adder circuit, the signal is inputted to a differential phase detection circuit 40, from which a phase difference signal in one symbol is outputted. The phase difference signal is inputted to a subtractor 44, the result of identification of the phase difference signal of an identification circuit 43 becomes an input signal to other subtractor circuit 41 and outputs an error signal being the difference. The correlation between the error signal and the signal delayed by one symbol at the circuit 40 is calculated by a multiplier circuit 45 and simultaneously the correlation between a complex conjugate value of the error signal and the input signal to the circuit 40 is calculated by a multiplier circuit 47. Output signals from the circuits 45, 47 are added by an adder 48, weighted by a weighting circuit 49 and the result is outputted to an adder circuit 39 via an accumulation circuit 50 as a revision of a drift compensation value. |
