The Journal of Korean Institute of Communications and Information Sciences (한국통신학회논문지)

The Korean Institute of Commucations and Information Sciences (한국통신학회)
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A Study on the Implemanation of IF Stage for Reducing Random Noise in the Mobile Communications

이동통신에 적용한 랜덤 잡음 제거를 위한 IF stage 구현에 관한 연구

  • 이은기 (한국이동통신㈜) ;
  • 박영철 (대유공업전문대학 전자통신과) ;
  • 차균현 (고려대학교 전파공학과)
  • Published : 1992.06.01
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Abstract

In this thesis, feedback circuit and FM detector applied to superheterodyne receiver to extract audio signal without random noise Is implemented. The feedback loop circuit converts 45MHz received signal to 4SiKHz If signal containing mess-age without random noise. Also the feedback loop provides the End local frequency, so narrowband BPF which is containing maximum Doppler frequency without message Is needed. Finally, quadrature FM detector extract audio signal by synthesis o350" shifted signal and ampli-tude limited signal. RSSI characteristics is measured and audio characteristics Is compared with existing If module.

마지막으로 Quadrature FM검파기를 사용하여 90$^{\circ}$전이된 신호와 진폭제한된 신호를 합성하여 오디오 신호를 추출하였고 RSSI특성을 측정하였으며 오디오 특성을 기존의 1F모듈과 비교하였다.

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