| 摘要 |
PROBLEM TO BE SOLVED: To make a phase locked loop circuit highly precise and fast which corrects a phase change in a frequency offset by detecting the phase shift of a receive signal from a replica signal generated from minimum pathmetric history information and the received signal and correcting it by a feedback circuit. SOLUTION: A phase rotator 102 corrects the phase shift of an input two-dimensional received signal, a minimum pathmetric history signal of viterbi algorithm is outputted from a minimum likelihood series estimation unit(MLSE) 103 to a replica generator 105 and convolutional operation between this and a previously found impulse response value of a transmission line is performed to generate a replica signal of the received signal. Then, a phase detector 106 finds a phase difference signal between the replica signal and the output signal of a delay element 104 and a inputs it to a voltage-controlled oscillator 108 through a filter 107 and it is outputted as a phase quantity to be corrected to the phase rotator 102 so that the phase correction of the receive signal is executed. Through this loop operation, phase variation represented by the frequency offset included in the received signal can be absorbed. |
