| 摘要 |
A dependent booster of a cellular phone prevents a deterioration of an intermodulation characteristic owing to double serial disposition of LNA when a body is connected to a booster, and removes a communication impossible state at a position near the base station. The control device of a low-noise receiving very high frequency amplifier of a dependent booster includes: a duplex filter(11) connected to a input duplex filter(23) via a RF cable; a receiving amplifier(12) for amplifying an output signal of the filter(11), and transmitting it to a center frequency part(I/F)(13); a center frequency part(13) for converting an amplified RF of the receiving amplifier(LNA)(12) to a center frequency(IF), and outputting a signal(RSSI) to a CPU(14); a center controller(16) for integrating CPU(15) with analog/digital converter(A/D)(14) as one body; an input part duplex filter(23) for a separation of a receiving/transmitting frequency; an output side filter(24) connected to an external antenna(30); a transistor(TR) for performing a switching function to control the receiving amplifier(22); a switch(21) connected to the CPU(15) and a control line; and a dependent booster(20) having an input part duplex filter(23) of a booster.
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