| 摘要 |
PURPOSE:To measure a frequency offset without error from an unknown data signal by applying decision through data point arrangement less than the normal data point arrangement and applying correction when the output of an adaptive equalizer is large. CONSTITUTION:Phase difference generating means 5, 6, 7, 8 compare the data point corresponding to the product of the output signal between frequency variable oscillation means 12, 13 applying frequency offset correction and the adaptive equalizer 1 with the data point less than the usual data point for the arrangement and select the data point closest to the data point representing the output signal of a multiplier 4 and generate a phase difference signal between the output signal of the multiplier 4 and the selected data point. Control means 9, 10, 11 give the phase difference signal to frequency variable oscillation means 12, 13 when the absolute value of the output signal of the multiplier 4 is larger than the prescribed value and do not give zero to the frequency variable oscillation means when the absolute value of the output signal of the multiplier is smaller than the prescribed value. Thus, control is not carried out. |
