| 摘要 |
PURPOSE: A frequency up converter card for a WLL(Wireless Local Loop) system is provided to compensate gain degradation according to the increase of temperature by adjusting an input power of a pin attenuator according to an output power monitored in an output power monitoring unit in an RFC(Radio Frequency Controller). CONSTITUTION: The second mixer(10) mixes a signal with 70MHz through the third filtering and amplifying unit(9) and a local signal with 2445-2465MHz generated in the second amplifying unit(4) and outputs an RF(Radio Frequency) signal with 2370-2400MHz. The fourth filtering and amplifying unit(11) removes a spurious signal to the RF signal with 2370-2400MHz outputted from the second mixer(10) and amplifies the RF signal. A variable amplifier(12) variably amplifies a gain of the RF signal with 2370-2400MHz through the fourth filtering and amplifying unit(11). The first coupler(13) couples the RF signal with 2370-2400MHz amplified by the variable amplifier(12) and outputs the coupled RF signal to a DISU. The second coupler(14) couples the RF signal with 2370-2400MHz coupled in the first coupler(13) again. An optical repeater port(15) outputs the RF signal with 2370-2400MHz outputted by the second coupler(14) to an optical repeater. An output power monitoring unit(16) monitors an output power of the RF signal with 2370-2400MHz outputted by the second coupler(14) and outputs the monitored result to an RFC so that the RFC adjusts input powers of the first and second pin attenuators(7,8) according to the monitored result.
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