| 摘要 |
<p>Provided is a tunable filter device having low loss, designed to expand out-of-band rejection, and able to achieve high selectivity. In the tunable filter device (3), a second tunable filter (7) having a second passband located within a first passband and having a bandwidth narrower than the bandwidth of the first passband is connected a first tunable filter (6) having the first passband, the second tunable filter (7) having a local oscillator (10) for generating a predetermined frequency signal, a mixer (8) for outputting the sum and the difference of the output signal of the first tunable filter (6) and the predetermined frequency signal output by the local oscillator (10), and an IF tunable filter (9) connected to the mixer (8).</p> |
