Broadband tuning circuit for receiving multi-channel signals over a broad frequency range

摘要

A broadband tuning circuit adapted for receiving both BS and CS broadcasting signals. The circuit includes an input circuit for receiving RF signals which associated with the BS and CS broadcasting signals, respectively, a splitter for splitting the RF signal to a low RF signal and a high RF signal, an oscillator for generating a local frequency signal, a first mixer for frequency converting the low RF signal to a first IF signal in the up-heterodyne fashion using the local frequency signal, a second mixer for frequency converting the high RF signal to a second IF signal in the down-heterodyne fashion using the local frequency signal, a selector for selecting either the first or the second IF signal and a demodulator for demodulating the information from the selected IF signal.