| 摘要 |
PURPOSE:To correct the effect due to deviation of a carrier frequency automatically by calculating vectors of signals after detection of delay and controlling a coefficient of a vector multiplier through the use of an output data after vector calculation and a data after discrimination of a threshold level. CONSTITUTION:An output of a delay detector 100 is subject to A/D conversion for each symbol in the timing of threshold level discrimination, that is, when an eye pattern is opened at maximum, vector calculation is applied to the result of A/D conversion to correct a deviation corresponding to the carrier frequency by shifting the deviation reversely. Vector multiplier outputs I1, Q2 and outputs I2, Q2 of threshold level discrimination circuits 104, 105 are inputted to a coefficient control circuit 106. A loop of the coefficient control circuit 106 is operated to have the relation of 2pi fT=-DELTAtheta and controls the carrier frequency that its deviation is always 0, then its is possible to make the effect of the deviation of the carrier frequency for each burst sufficiently small. |
