| 摘要 |
PURPOSE:To revise control constants of the circuit at its mounting stage without changing the characteristic of the circuit to reduce malfunction of the circuit due to an external noise. CONSTITUTION:When a multiple alpha of a 1st current arithmetic circuit 21 multiplying a current corresponding to alpha phase difference outputted from a charge pump 2 by the multiple a is changed, a phase difference current conversion coefficient Kp of a phase difference current conversion circuit is changed. Furthermore, a 2nd current arithmetic circuit 41 multiplies a current corresponding to a voltage received from a filter circuit 3 by a multiple alpha, and when the multiple alpha is varied by a 2nd multiple factor conversion circuit 42, a voltage frequency conversion coefficient Kv of a voltage controlled oscillator circuit 4 is changed. When either or both of the 1st and 2nd multiple factor conversion circuits 22,42 are changed, a ratio of the Kp to the Kv is changed while keeping the relation that the KpXKv is constant. Thus, the effect of an output signal 200 intruded in circuit components of the PLL circuit is adjusted at minimum. |
