| 摘要 |
The present invention provides a switchable wide band receiver front end for a multiband receiver comprising a broadcast signal receiving means (1) for receiving broadcast signals within multiple receiving frequency bands, wherein each frequency band is divided into a plurality of channels; a wideband low noise amplifier (2) connected to said broadcast signal receiving means for amplifying the broadcasted signals of all receiving frequency bands outputting an amplified output signal which is branched to multiple switches (11, 12, 13) of a switching means (10), wherein the number of said switches (11, 12, 13) corresponds to the number of receiving frequency bands; multiple filters (22, 23, 24) each connected to one of said switches (11, 12, 13), wherein each filter has a bandpass filterering characteristic to pass all signals within an associated receiving frequency band; a mixing means (30) connected to the output side of each filter mixing the filtered signal with a locally generated mixing signal from a frequency synthesizer to produce a intermediate-frequency signal; and a control means (14) outputting a first control signal to said switching means (10) for switching on one of said switches wherein one of said multiple receiving frequency bands is selected and outputting a second control signal to said frequency synthesizer (31) to generate a mixing signal corresponding to the selected receiving frequency band. <IMAGE>
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