| 摘要 |
PURPOSE:To enable recover automatic tuning immediately even the receiver is in a normal reception mode by holding a defeat voltage and error voltage in the same states as a normal tuning state by providing a clamper circuit. CONSTITUTION:While clamper circuit 100 is in operation, the upper limit of the voltage of signal line 9 is clamped to the voltage of connection point 13 and when it increases more, electric current is flowed through transistor TR113 to decrease it down to the voltage of connection point 13; and the lower limit of the voltage of signal line 9 is clamped to the voltage of connection point 12 and when it decreases more, electric current is flowed to diode 115 to increase it up to the voltage of connection point 12. Further, the voltage of signal line 8 is clamped lower than the voltage of connection point 14 and when it increases higher, electric current is flowed to TR114 to decrease it down to the voltage of connection point 14. This low voltage is equivalent to a voltage showing the existence of a synchronizing signal in detecting circuit 6 and even if a defeat voltage showing the nonexistence of the synchronizing signal is outputted from circuit 6, the upper limit of the voltage of signal line 8 is clamped to the voltage of connection point 14. |
