Tv tuner and tuning method

TV tuners and methods thereof are provided. A TV tuner includes a first frequency converting circuit, a second frequency converting circuit, and a demodulator. The first frequency converting circuit, switchable between a first operating mode and a second operating mode, receives an RF signal and outputs a converted signal by performing highside injection on the RF signal in the first operating mode and performing frequency addition on the RF signal in the second operating mode. The second frequency converting circuit performs a down conversion on the converted signal from the first frequency converting circuit to obtain an intermediate frequency signal. The demodulator demodulates the intermediate frequency signal and outputs a baseband frequency signal comprising video and audio signals.