| 摘要 |
PURPOSE: An active mixer for CDMA/PCS is provided to reduce the volume of the mixer and to minimize the loss of receiving signals by improving IMD(Intermodulation Distortion) characteristic and a noise index. CONSTITUTION: An electric supply apply part(100) applies driving power supply to the first FET(Field Effect Transistor)(501) and the second FET(502) mounted on a frequency extracting part(500). A DC current passing part(200) is formed with a coil(L1) and a condenser(C1) parallel connected with a signal output end of the electric supply apply part(100) for passing only DC current in driving power supply outputted from the electric supply apply part(100) through a circuit. The first high pass filter(300) is formed with a condenser(C2) and a coil(L2) connected parallel with a signal output end of a voltage control oscillator(5) for passing only high band frequency component in local power frequencies outputted from a PLL(Phase Lock Loop) and passing through the voltage control oscillator(5), through the first FET(501). The second high pass filter(400) is formed with a condenser(C3) and a coil(L3) connected parallel with a signal output end of a RF SAW filter(3) for passing only high band frequency component in RF signals outputted from a low noise amplifier and passing through the RF SAW filter(3), through the first FET(501). The frequency extracting part(500) is formed with the first FET(501) and the second FET(502) for extracting frequency corresponding to the remainder of the local power frequency passing the first high pass filter(300) and the RF signal passing the second high pass filter(400), and outputting to an intermediate frequency passing filter(700). A bias part is formed with a resistance(R1) and a condenser(C4) parallel connected with the source terminal of the second FET(502) for stabilizing the whole circuit. The intermediate frequency pass filter(700) is formed with a coil(L4) and a condenser(C5) for receiving frequency corresponding to the remainder of the local power frequency and the RF signal outputted from the frequency extracting part(500).
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