The search functionality is under construction.

Author Search Result

[Author] Sung Uk KIM(1hit)

1-1hit
  • A New Predistorter Using Low Frequency Intermodulation Signals Injection of a Harmonic Generator

    Young KIM  Hyung Soon JANG  Sung Uk KIM  Ik Soo CHANG  Yong Chae JEONG  

     
    PAPER

      Vol:
    E86-C No:8
      Page(s):
    1709-1714

    In this paper, a predistorter using low frequency intermodulation (IM) signals is proposed. The harmonic generator of the proposed predistorter that consists of a hybrid coupler and four diodes biased separately extracts a second order low frequency IM signal. And with multiplication of second order IM signals, fourth order IM signal is obtained. A vector modulator, modulate fundamental signal with low frequency IM signals, generates predistortion IM signals and controls amplitude/phase of them with modulation factors. As a result, this predistorter is suppressed individual order intermodulation distortion signals of power amplifier effectively. The suggested predistorter has been manufactured to operate in Korea PCS base-station transmitting band (1840-1870 MHz). The test results show that the third order IM is cancelled more than 20 dB and the fifth order IM is cancelled about 10 dB for CW two-tone signals. Also, it's improved the adjacent channel power ratio (ACPR) more than 10 dB for CDMA (IS-95) signals.