| 摘要 |
PURPOSE: A portable phone having improved IMD(InterModulation Distortion) characteristics using a low noise amplifier is provided to enhance IMD characteristics without having an effect on sensitivity by adjusting gain according to an input signal using a low noise amplifier, to minimize the quantity of components using a single element and to reduce characteristic deviation between portable phones, due to the characteristic difference between components, by a compensation table. CONSTITUTION: A receiving unit of a portable phone having improved IMD characteristics is composed of a duplexer(10), an MSM(Mobile Station Modem)(20), a low noise amplifier(30), an RF filter(40), a mixer(50) and an intermediate frequency filter(60). The duplexer(10) outputs an RF type signal to the low noise amplifier(30). The MSM(20), having a database for low noise amplifier gain characteristics, outputs a suitable gain signal to the low noise amplifier(30) according to the signal outputted from the duplexer(10). The low noise amplifier(30), receiving the RF signal outputted from the duplexer(10), amplifies it according to the gain signal outputted from the MSM(20) and outputs the amplified signal to the RF filter(40). The RF filter(40) filters the signal outputted from the low noise amplifier(30) and outputs it to the mixer(50). The mixer(50) mixes the signal outputted from the RF filter(40) with a local signal and outputs the mixed signal to the intermediate frequency filter(60). The intermediate frequency filter(60) removes a distortion component from the signal outputted from the mixer(50).
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