| 摘要 |
<p>A multiband tuning system produces an IF signal from RF signals residing in, in the order named, a first broadcast band, a first cable band, a second broadcast band and a second cable band. A control device generates a tuning signal having a magnitude determined by the frequency of a selected channel. A first filter selects RF signals corresponding to channels selected in a first tuning band including the first broadcast band and a lower frequency portion of the first cable band in response to the tuning signal. A second filter selects RF signals corresponding to channels selected in a second tuning band including an upper frequency portion of the first cable band, the second broadcast and the second cable bands in response to the tuning signal. A selection device enables operation of the first filter when the selected channel is within the first tuning band and enables operation of the second filter when the selected channel is in the second tuning band.</p> |
