Optimal (Bandpass) Continuous-Time ZA Modulator
نویسنده
چکیده
A systematic technique for designing a continuous-time sigma-delta modulator @AhI) is presented. The continuous-time m open-loop transfer function is obtained by the pulse-invariant transformation of its discrete-time equivalent. This method results in an inherently stable XAM and does not need any loss factor to make the modulator stable, and so provides the maximum achievable signal-to-noise ratio. Properties of the continuous-time XAM are described. The technique has been applied to conventional lowpass and bandpass XAMs, and a general fourth-order bandpass example is given to illustrate the theory.
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