| 摘要 |
PURPOSE:To prevent the production of a spurious signal and to receive signals of broad band stably with simple constitution, by taking a cable TV as a duplex mixing system, in receiving broad band of each channel of VHF, cable TV and UHF. CONSTITUTION:The 1st VHF channel input terminal 16 is connected to a VHF tuner 2, and an IF output terminal 7 is connected to the tuner 2. A CATV tuner 4 is connected to the 2nd cable TVCATV channel input terminal 17, a switching circuit 23 connected to the post stage of a tuner 4 is connected to the 3rd UHF channel input terminal 18, the circuit 23 is connected to a UHF tuner 5, and this tuner 5 is connected to the tuner 2. At the reception of input signal from a terminal 17, the tuner 4 is for the reception of upper side wave of differential type and the tuner 5 is for the reception of lower side waves. At the reception of input signal from a terminal 18, the tuner 5 is operated for the reception of upper side waves of differential type, allowing to suppress the production of spurious signals with simple constitution. |
