| 摘要 |
PURPOSE: An RF(Radio Frequency) receiver is provided to obtain a baseband signal and an IF(Intermediate Frequency) in which an image signal is cancelled by selectively inactivating frequency converters and obtaining a desired IF. CONSTITUTION: An LNA(Low Noise Amplifier)(103) amplifies a signal received through an antenna(101). The first frequency mixer unit including frequency converters(104,109) receives a signal outputted from the LNA(103), and outputs an in-phase signal and a quadrature phase signal of an IF. Variable gain amplifiers(105,110) amplify the signals outputted from the first frequency mixer unit. The second frequency mixer unit including frequency converters(112,114,116,117) receives the signals outputted from the variable gain amplifiers(105,110), and outputs an in-phase signal and a quadrature phase signal of a baseband. Switches(113,115) selectively inactivate the frequency converters(112,114,116,117) of the second frequency mixer unit. Adders(118,121) add the in-phase signal and the quadrature phase signal outputted from inactivated frequency converters of the second frequency mixer unit.
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