| 摘要 |
PURPOSE:To attain high-speed lead-in by changing a constant of a loop filter extending over two or more steps and making the change when the loop completes leading-in perfectly. CONSTITUTION:Resistances RS1, RS2, RS3 are connected to an end of switches SW1-SW3 respectively. These resistances are selected to RS1<<R1, RS2<<R2, RS3<<R3, and used to reduce switching noises at the time of switching the switches SW1-SW3. In turning a power source on, on signals are inputted to controlling signals X, Y, Z, and when it is so structured that SW1, SW2, SW3 are turned on by the on signals, a loop of circuit of the loop filter is constituted at RS1, RS2, RS3 and C, and two time constants tau1=C(RS2+RS3), tau2=CRS1 become small, and thereby high-speed lead-in is realized. |
