| 摘要 |
PURPOSE:To estimate correctly the difference of phase between the symbol timing of the analog demodulation signal and a reference clock regardless of the value of the input phase difference, by eliminating the discontinuous points of the phase detection characteristics of a phase detector. CONSTITUTION:The detection outputs of plural times of a phase detector 1 are supplied to an absolute value circuit 2 for output of the absolute value of each detection output. Furthermore, the average of the absolute value of those detection outputs is calculated by an averaging circuit 3. While the positive and negative codes of the output the detector 1 are decided by a code deciding circuit 4 in parallel with those said actions. Then a majority circuit 5 decides the numbers of positive and negative codes contained in the output of the circuit 4. Then the circuit 5 outputs +1 in case the number of positive codes is larger then or equal to the number of negative codes and then -1 if the number of negative codes is larger than that of positive codes respectively. The detection output emerges only at the positive side (since the absolute value is secured) and therefore the discontinuous points are eliminated. |
