| 摘要 |
PURPOSE: A CDMA(Code Division Multiple Access) optical repeater receiving apparatus using a digital signal transmitting apparatus is provided to perform a digital signal transmission from a remote optical repeater to a CDMA base station, thereby preventing a lowering of performance at a reception end generating in an analog signal transmission. CONSTITUTION: The receiving apparatus consists of a remote optical repeater(210) and a CDMA master base station(220). The remote optical repeater(210) includes a reception antenna(211) for receiving an RF signal. A low noise amplifier(AMP1) amplifies the RF signal inputted from the antenna(211). A band pass filter unit(212) passes the amplified signal. A reception amplifier(AMP2) amplifies and outputs the signal output from the filter unit(212) as a proper gain. A frequency mixer(213) changes the signal from the amplifier(AMP2) into a baseband frequency band signal. An analog/digital converter(214) converts the baseband signal into a digital signal. An automatic gain control circuit(215) controls the gain from the amplifier(AMP2) in order to make the gain of the signal maintain constantly. A digital delay unit(216) receives the converted signal and then equals the round trip delay time between repeaters. A digital photoelectric converter(217) receives an optical signal from an another optical repeater and then converts the signal into an electric signal. A digital adder(218) adds the digital signal of the another optical repeater to the digital signal of the digital delay unit(216). A digital electrophotic converter(219) converts the digital signal of the digital adder(218) into an optical signal and then output the signal to an another optical repeater as an input signal, or outputs the optical signal to the CDMA master base station(220) through an optical cable when the remote optical repeater is a final end remote optical repeater.
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