| 摘要 |
PURPOSE: An RF-IF(Radio Frequency-Intermediate Frequency) separation type W-WLL(Wideband-Wireless Local Loop) terminal is provided to configure the bandwidth of IFs identically, so as to share an IF module. CONSTITUTION: In an outdoor unit(100), a duplexer protects a receiver against a transmission output upon transmission and supplies echo signals to the receiver upon receiving, in order to use an antenna in both of the transmission and the receiving. An LNA(Low Noise Amplifier) receives the signals passing the duplexer for low noise amplification. An RF SAW(Surface Acoustic Wave) removes frequencies existing in different bands from the amplified signals. A downward frequency converter converts the signals whose other band frequencies are removed into IFs. And a multiplexer simultaneously transceives the converted signals as a plurality of individually independent signals by dividing one line or transmission line. In an indoor unit(200), a multiplexer simultaneously transceives the signals transmitted from the outdoor unit(100) as a plurality of individually independent signals by dividing one line or transmission line. A demodulator converts the signals received through the multiplexer into baseband signals. A baseband BPF(Band Pass Filter) filters the demodulated baseband signals. An A/D(Analog-to-Digital) converter converts the filtered signals into digital signals. A digital baseband processor delivers the digital signals to a connected DSP(Digital Signal Processor) modem, for interfacing with each unit. An analog converter converts CDMA(Code Division Multiple Access) digital information into baseband analog signals, if signals are transmitted from the each interfaced unit. A modulator modulates the converted analog signals. An IF gain control amplifier varies the level of the modulated signals. And a BPF(Band Pass Filter) filters the varied signals.
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