| 摘要 |
PURPOSE: A band pass filter of mobile telephone and a control method thereof are provided to decrease unnecessary components in high frequency signal by using selectively the band pass filter proper to the current channel according to the channel information of a base station. CONSTITUTION: A duplexer(11) controls a stream of high frequency signal received from an antenna(10), and transmits the high frequency signal to a high frequency receiving unit. The received high frequency signal is amplified in a low noise pre-amp(12), and then inputted to one of two receiving band pass filter(14,15). A controller(30) of the mobile terminal switches the first switch(13) and the second switch(16) by using the channel information of a base station. So that the receiving band pass filter(14,15) to be inputted the current receiving high frequency signal is selected. The receiving band pass filter(14,15) restrains the noise occurred by amplification in the receiving high frequency signal, and passes only the receiving high frequency signal of the applicable the frequency band. A frequency mixer(17) mixes the filtered receiving high frequency signal with local signal to down the signal of intermediate frequency band.
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