Journal of the Institute of Electronics Engineers of Korea SD (대한전자공학회논문지SD)

The Institute of Electronics and Information Engineers (대한전자공학회)
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A Tunable Bandpass SC Sigma-delta Modulator For Intermediate Frequency With Novel Architecture

IF 대역의 중심주파수 조절을 위한 새로운 구조를 갖는 4차 SC Bandpass Sigma-Delta Modulator

  • Jo, Se-Jin (Division of Electronics and Information Engineering, Chonbuk University) ;
  • Cho, Seong-Ik (Division of Electronics and Information Engineering, Chonbuk University)
  • 조세진 (전북대학교 전자정보공학부) ;
  • 조성익 (전북대학교 전자정보공학부)
  • Received : 2010.10.29
  • Accepted : 2010.12.15
  • Published : 2011.01.25
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Abstract

In this paper, Intermediate frequency tunable 4th order Switched Capacitor(SC) bandpass Sigma-Delta(${\Sigma}-{\Delta}$) modulator using feedback integrator using feedback integrator coefficients is proposed. The center frequency of the modulator can be easily changed than conventional structure because of a number of integrator coefficients which is decided rate of capacitors in circuit is reduced. In addition additive clocks and additive clock generating circuit are not necessary. The purposed modulator was implemented in $0.18{\mu}m$ CMOS technology. The resolution of the modulator within 200 kHz bandwidth and 80 MHz sampling frequency under fin = 15 MHz, 20 MHz, 25 MHz are over 12 bit.

본 논문은 Feedback 적분기 계수를 이용하여 IF 대역의 중심주파수 조절이 가능한 Bandpass SC Sigma-de1ta 변조기를 제안한다. 제안한 구조는 Feedback loop에 적분기를 추가함으로서 동일 차수의 기존 구조에 비해 중심주파수 조절에 필요한 계수와 계수를 결정하는 커패시터의 수를 줄이고 기본적인 비중첩 클락 이외의 추가적인 클락 및 클락에 대한 부가회로가 필요하지 않다. 따라서 설계가 용이하며, 고차 구성이 가능하면서 더 높은 해상도를 가진다. $0.18{\mu}m$ CMOS 공정을 이용하여 설계하였으며, 200 kHz의 대역폭, 80 MHZ의 샘플링 주파수에서 15 MHz, 20 MHz, 25 MHz 의 중심주파수 일 때 12 bit 이상의 해상도를 가진다.

Keywords

References

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