Variable centre frequency resonator based bandpass Σ-Δ modulator
Al-Janabi, M., Kale, I. and Morling, R.C.S. 1997. Variable centre frequency resonator based bandpass Σ-Δ modulator. Electronics Letters. 33 (24), pp. 2008-2009. https://doi.org/10.1049/el:19971370