| 摘要 |
PURPOSE:To shorten the synchronizing time of a phase locked loop circuit and to increase the pull-in range by eliminating the undesired signals in the synchronizing process of the phase locked loop circuit. CONSTITUTION:A triangular wave type phase comparator 11 detects the phase difference between an input signal X and an output signal Y to obtain an output signal Y1. A loop filter 12 smoothes the signal Y1 to turn it into an output signal Y2. A loop filter 13 smoothes the signal Y2 into an output signal Y3. A VCO 14 oscillates a signal of the frequency accordant with the value of the signal Y3 and turns the signal into an output signal Y4. A phase difference (3/2)pi detector 16 compares the signal Y2 with the signal Y3 in terms of the voltage value to detect the phase difference (3/2)pi and defines this result as an output signal Y5. An output switch 15 inverts or does not invert the signal Y4 in accordance with the signal Y5 and outputs the signal Y4 as an output signal Y. |
