The Transactions of The Korean Institute of Electrical Engineers (전기학회논문지)

The Korean Institute of Electrical Engineers (대한전기학회)
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Tunable Bandpass 4th Order SC Sigma-delta Modulator with Novel Structure

새로운 구조의 Tunable 4차 SC Bandpass Sigma-Delta 변조기

  • Received : 2010.12.31
  • Accepted : 2011.01.26
  • Published : 2011.02.01
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Abstract

Tunable SC(Switched Capacitor) bandpass ${\Sigma}-{\Delta}$(Sigma-Delta) modulator used in wireless system receiver occurs a signal attenuation according to tuning of center frequency in signal bandwidth. In this paper, tunable bandpass 4th order SC bandpass ${\Sigma}-{\Delta}$ modulator with novel structure is proposed for rejection of signal attenuation in signal bandwidth. The existing structure uses a ten variable coefficient values for rejection of signal reduction in the modulator. But the proposed structure only use a two variable coefficient values for rejection of signal attenuation in the modulator. Also, an adder and comparator is replaced with a comparator having 4 inputs in the modulator. Therefore, the existing structure has one more OP-AMP. The purposed modulator was designed in $0.18\;{\mu}m$ CMOS technology. The resolution of the modulator within 310 kHz bandwidth and 40 MHz sampling frequency under 6.67 MHz, 10 MHz and 13.33 MHz intermediate frequency are over 10 bit.

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References

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  2. G.Yin and W. Sansen, "A high-frequency and high-resolution fourthorder sigma-delta A/D converter in BiCMOS technology" IEEE J. Solid State Circuits, vol.29, pp. 857-865, Aug. 1994. https://doi.org/10.1109/4.297688
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