| 摘要 |
PURPOSE:To avoid deflection of a meter pointer up to its limit range when a power supply switch is turned on and off by delivering the pulse output of an IC having a PLL synthesizer for tuner under the prescribed conditions. CONSTITUTION:When a power supply switch is turned on, the voltage of a DC power supply 9 has a rise. Thus, the voltage of a terminal 8 is set at a high level, and an IC1 starts a pulse output operation. However the IC1 discontinues this action until the voltage of the terminal 8 is set at a high level. At the same time, the output voltage of a terminal 14 is set at a low level. Therefore the output of an integrator is set at zero to give no deflection to the pointer of a display meter 7. When the voltage of the terminal 8 is set at a high level, the IC1 starts its pulse output operation. At the same time, the output of the terminal 14 is set at a high level. Then the positive voltage appears at a terminal 2 and then the positive pulse voltage whose duty width is increased as the reception frequency increases appears at the terminal 2. Then the input of the integrator is set at zero when the voltage of the terminal 8 is set at a low level. Thus the pointer of the meter 7 has no deflection. |
