| 摘要 |
PURPOSE: An amplifier of an up-converter in an IMT-2000 base station system is provided to amplify a CDMA signal having big power, without distortion, thereby improving the capacity of the up-converter. CONSTITUTION: The first coupler(100) couples an input CDMA signal for outputting in two ways. The second coupler(200) combines the signal output from the first coupler(100) with the second harmonic component input through the other input end for outputting. The first amplifier(300) amplifies the combined signal to a predetermined level. The third coupler(400) transmits the signal amplified at the first amplifier(300) to the fourth coupler(1000) and simultaneously couples the second harmonic component for outputting. The first transmission line(500) phase-shifts the second harmonic component at 180 degrees for transmitting to the second coupler(200) to prevent intermodulation characteristic from being lowered in case that power of an input signal increases. The fifth coupler(600) combines the signal output from the first coupler(100) with the second harmonic component input through the other input end for outputting. The second amplifier(700) amplifies the combined signal to a predetermined level. The sixth coupler(800) transmits the signal amplified at the second amplifier(700) to the fourth coupler(1000) and simultaneously couples the second harmonic component for outputting. The second transmission line(900) phase-shifts the second harmonic component at 180 degrees for transmitting to the fifth coupler(600) to prevent intermodulation characteristic from being lowered in case that power of an input signal increases. |
