リアルゼロ系列直交同期検波器  [in Japanese] Quadrature Coherent Detector Using Real Zeros  [in Japanese]

Search this Article

Author(s)

Abstract

受信アナログ信号から同相・直交成分のディジタル信号を生成するIQ検波において,リアルゼロ系列から波形を再生する技術を適用し,受信信号の飽和増幅出力からIQ波形を生成する方法を提案する.この方法では受信線形増幅における非線形歪抑圧の要求が大幅に緩和される.そのため,今後のRFとベースバンドを一体化したSi-CMOS技術に適合している.まず変調された受信信号の帯域外に正弦波を加える.その後信号を増幅し直交検波を行う.受信増幅器としてはある一定レベル以下には線形増幅の領域があり,それ以上では飽和する飽和形線形増幅器と,線形領域がない完全なリミタ形の2種類について検討する.リアルゼロ系列の時刻をサンプリングするTDCには線形補間形と単純量子化形の2種類を検討する.計算機シミュレーションにより提案した検波器の性能を明らかにする.最大変調周波数の64倍の搬送周波数で信号を送信する狭帯域信号に対して,ピーク振幅の1/32以上が飽和する歪の大きな受信増幅器でもEVMが-50dB以下の高い精度で検波波形を再生できることを示す.また,それ以上の歪の増幅器の場合,EVMが-27dB程度と再生波形の精度が大きく劣化することを示す.

This report proposes a coherent quadrature detector that performs signal recovery using real zero, so as to extract in-phase and quadrature components from received signals distorted by a saturated amplifier. Since the proposed detector is robust to non-linear distortion due to a receive power amplifier, the detector is suitable for joint implementation of RF and baseband circuits by Si-CMOS. In the first process, the detector adds a sinusoidal wave with its frequency out of the band, to the received signal. After amplifying the resultant signal, it performs quadrature detection using the real zero. This report considers two kinds of the receive amplifier; one operates as a linear amplifier when the input level is less than a threshold, while working as a saturated amplifier when the input level exceeds the threshold. The other is the ideal limiter amplifier that dose not have any linear regions. In addition, the proposed detector requires time digital converters (TDCs) that measure the time (real zero) when the composite signal coincides with a zero level. Two kinds of TDCs are considered; linear interpolation and simple quantization types. Computer simulations demonstrate the effectiveness of the proposed detector under the condition that the carrier frequency is 64 times as high as the maximum frequency of the modulated signal. It is shown that error vector magnitude (EVM) of the recovered in-phase and quadrature components is less than -50dB ever when the threshold level is one -32nd that causes severer distortion degrades accuracy of the signal recovery and reduces the EVM to -27dB.

Journal

  • IEICE technical report

    IEICE technical report 109(130), 137-142, 2009-07-09

    The Institute of Electronics, Information and Communication Engineers

References:  12

Codes

  • NII Article ID (NAID)
    110007359463
  • NII NACSIS-CAT ID (NCID)
    AN10060822
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    09135685
  • NDL Article ID
    10308517
  • NDL Source Classification
    ZN33(科学技術--電気工学・電気機械工業--電子工学・電気通信)
  • NDL Call No.
    Z16-940
  • Data Source
    CJP  NDL  NII-ELS 
Page Top