A television tuner employs a triple-conversion architecture to translate VHF/UHF TV signals to various standard IF frequencies. The television tuner includes a harmonic rejection mixer, a first image rejection mixer and a second image rejection mixer. The television tuner receives a television signal. The harmonic rejection mixer up-converts the television signal into a first IF signal according to a first reference signal with a fixed frequency. The first image rejection mixer further up-converts the first IF signal into a second IF signal according to a second reference signal with a tunable frequency. The second image rejection mixer down-converts the second IF signal into a third IF signal according to a third reference signal with a tunable frequency.