An anti-aliasing filter inspired by continuous-time ΔΣ modulation

An anti-aliasing filter that incorporates a sampler is proposed to precede noise-shaping analog-to-digital converters (ADCs), such as discrete-time DeltaSigma modulators. The architecture of the proposed anti-aliasing filter is inspired by the implicit anti-aliasing filtering property of CT DeltaSigma modulators. However, contrary to CT DeltaSigma modulators, the proposed anti-aliasing filter is not sensitive to clock jitter. Furthermore, its key characteristics include: (1) higher suppression of aliases, compared to a Butterworth filter of the same order (same number of opamps); and (2) high-pass shaping of the sampling errors. Its performance advantages are derived theoretically and then confirmed through behavioural simulations.