Patent ID: 7249368

Claim:
A tuner apparatus comprising: a mixer circuit for using first oscillation signals to upwardly frequency-convert terrestrial TV broadcast signals or CATV broadcast signals supplied from a terrestrial TV broadcasting receiver or a CATV broadcasting receiver into signals that fall within an occupied bandwidth of intermediate-frequency signals of satellite TV broadcasting signals supplied from a satellite TV broadcasting receiver, said mixer circuit outputting first intermediate-frequency signals; a quadrature detector circuit to which said intermediate-frequency signals of said satellite TV broadcasting signals and said first intermediate-frequency signals from said mixer circuit are inputted; and an oscillator circuit for supplying second oscillation signals of the occupied bandwidth of said intermediate-frequency signals of said satellite TV broadcasting signals to said quadrature detector circuit, wherein when said tuner apparatus receives satellite TV broadcasting signals, said oscillator circuit supplies said second oscillation signals of the occupied bandwidth and of a predetermined phase to said quadrature detector circuit where said satellite TV broadcasting intermediate-frequency signals supplied thereto are demodulated into baseband signals by using said second oscillation signals, and wherein when the tuner receives said terrestrial TV broadcast signals or said CATV broadcast signals, said oscillator circuit supplies said second oscillation signals to said quadrature detector circuit where said first intermediate-frequency signals supplied thereto are demodulated into baseband signals by using said second oscillation signals, wherein said mixer frequency-converts only said TV broadcast signals or said CATV broadcast signals and does not frequency-convert said satellite TV broadcasting signals.