| 摘要 |
<p>The tuner comprises an RF input for receiving a high frequency signal, a downconverter including a mixer for downconverting the high frequency signal, an IF filter coupled to an output of the mixer, an SAW filter coupled to an output of the IF filter and a gain-controlled IF amplifier coupled to an output of the SAW filter for providing an amplified IF signal for a subsequent demodulator. The IF filter includes a controllable damping stage which is in particular usable for improving the noise performance of the tuner. The tuner is designed in a preferred embodiment for reception of analog and digital television signals and the controllable damping stage provides a damping in case of reception of an analog television signal for improving a signal/noise ratio of the analog television signal. The damping stage comprises for example a switching stage utilizing one or several varactor diodes as damping elements.</p> |
