| 摘要 |
PURPOSE:To attain the quick and stable receovery of a carrier by keeping the frequency of an oscillation means to a mean value of a carrier frequency of the past burst at a time slot when no burst is inputted. CONSTITUTION:The phase of a burst carrier signal 101 and that of a reference carrier signal 104 from a voltage controlled oscillator VCO 5 are compared by a phase comparator 1 and the result is outputted via a low pass filter 2 as an error signal 102. In this case, the oscillation frequency of the VCO 5 is controlled by the sum between the signal 102 and a mean value signal 103 from an averaging circuit 3 and neither the signal 101 nor the signal 102 exists in the time slot when no burst is inputted. Thus, the control input of the VCO 5 is kept to a frequency corresponding to the signal 103, that is, the mean value of the carrier frequency of the past burst to decrease the initial frequency offset. Thus, the quick and stable carrier is recovered. |
