| 摘要 |
PROBLEM TO BE SOLVED: To enable the followup of path through a synchronous followup device by finding the average value of power of a correlative value outputted from a correlator, comparing that average value with a prescribed threshold value and changing the correlative length of the correlator crorresponding to the result. SOLUTION: An early correlator Corr E1 outputted from a normalizer 14E and a late correlator Corr L1 outputted from a normalizer 14L are respectively outputted to a power comparator 17. Then, an average circuit 20 of the comparator 17 finds the average value of power of the early correlative value Corr E1 and the late correlative value Corr Ll for fixed time. Next, a comparator circuit 21 compares the average value of this power with a threshold value Pow TH of power. When the average value of power is lower than the threshold value, a control signal C1 for increasing a cumulative number N of a cumulative adder 13E is outputted to correlators 10E and 10L. In this case, the constant N is made K-fold corresponding to the signal C1. Therefore, even when a received signal component is too less to follow up, the constant of the correlative length is adaptively extended and an S/N is improved. |
