| 摘要 |
PROBLEM TO BE SOLVED: To suitably output a high frequency input signal to a tuner respectively in the case that an antenna reception terminal power is strong or weak. SOLUTION: A detection circuit 14 detects an RF input signal from an antenna and outputs a DC signal in response to an antenna receiving end power to a 1st changeover on/off circuit 15. When a voltage of the DC signal is higher than a prescribed threshold voltage, the 1st changeover on/off circuit 15 is closed and a 2nd changeover on/off circuit 16 is open. Thus, only a signal via an attenuator 12 or the like is outputted to a tuner. When the voltage of the DC signal is a prescribed threshold voltage or below, the 1st changeover on/off circuit 15 is open and the 2nd changeover on/off circuit 16 is closed. Thus, only a signal via an amplifier 13 or the like is outputted to the tuner.
|
