Video tuning system

The utility model discloses a video turning system, which comprises an amplifier circuit, a coupling amplifier circuit and a tuner TUA6039, wherein the amplifier is connected with a radio frequency input end, the coupling amplifier circuit is connected with the amplifier circuit, the tuner TUA 6039 is connected with the coupling amplifier circuit, a radio frequency switch circuit is connected between the turner TUA 6039 and the radio frequency input end, and the turner TUA 6039 is connected with a local oscillator circuit and a 12C bus. Besides, the tuner TUA6039 is connected with a medium frequency amplifying chip TDA9886 after being connected with a filter circuit. The turner TUA6039 controls ports of a switch circuit, and when testing analog signals, the amplifier circuit is switched off via the switch circuit, thereby eliminating interference after amplifying. Besides, when testing digital signals, the amplifier circuit is switched on via the switch circuit, and then enough gain isachieved to increase dig