A new technique for designing an LC bandpass DeltaSigma modulator is presented. This method is based on pulse shaping of a DAC output signal such that one can realize a desired (arbitrary) loop transfer function. Especially for higher-order modulators where extra LC sections are added, sufficient number of parameters are provided in the feedback loop. It is shown that by creating more degrees of freedom one can achieve the maximum SNR in a given modulator order without constraining the noise transfer function of the modulator.
Omid Shoaei, W. Martin Snelgrove