Patent ID: 7013124

Claim:
A broadband tuner comprising: an input terminal supplied with a high-frequency digital signal; a first fixed filter, allowing L band frequency to pass through, connected to said input terminal; a second fixed filter, allowing V band frequency to pass through, connected to said input terminal; a first changeover switch having an output of said first fixed filter connected to one terminal thereof and an output of said second fixed filter connected to the other terminal thereof; a first mixer having a common terminal of said first changeover switch applied to one input thereof and an output of a first local oscillator connected to the other input thereof via a second changeover switch; a third fixed filter, allowing L band frequency to pass through, connected to an output of said first mixer; a second mixer having an output of said third fixed filter applied to one input thereof and an output of a second local oscillator connected to the other input thereof; an output terminal having an output of said second mixer applied thereto; a first PLL circuit loop-connected to said first local oscillator; a first data terminal for supplying said first PLL circuit with data; a second PLL circuit loop-connected to said second local oscillator; and a second data terminal for supplying said second PLL circuit with data, wherein, when said first changeover switch selects the output of said first fixed filter, said second changeover switch is turned off such that said first mixer is operated as an amplifier and an oscillation frequency of said second local oscillator is controlled based on data supplied to said second data terminal, whereby a signal output from said third fixed filter is channel-selected and converted into a predetermined frequency in said second mixer, and when said first changeover switch selects the output of said second fixed filter, said second changeover switch is turned on and an oscillation frequency of said first local oscillator is controlled based on data supplied to said first data terminal, whereby a channel selection is performed while the V band frequency is converted into L band in said first mixer, and an output of said third fixed filter is converted into a predetermined frequency in said second mixer.