Sigma-delta signal processing

Some authors proposed the extension of sigma-delta to implement filters, amplitude and phase modulators, correlators, adders, compandors, expanders, digital synthesizers, phase-locked loop etc. We believe that ΣΔ should be seen as a novel domain for signal processing in parallel with continuous-time, sampled-data and digital. Interface blocks, operators available and the potential of the technique are discussed, and a wide set of applications like adder, multiplier, compandor, expander, AGC, synthesizers PLL, oscillators, filters are discussed