Continuous-time /spl Delta//spl Sigma/ modulators using distributed resonators

Design and implementation of a band-pass sigma delta modulator with distributed resonators

“…While this reduces the peak SNR, it also prevents high resonances values. Also a voltage clamp can be placed at the output of each transconductor [7].…”

“…Deviations from the ideal resonator length perturbate the pole and zero locations of the NTF. This results in a degradation of the modulator performance [7]. However, this problem can be solved by placing a parallel trimming capacitor C p (see Fig.…”

“…In this paper we present the basic theory, the design and the experimental validation of a new band-pass CTSD modulator that uses transmission lines (TL) as resonators instead of LC or g m -C circuits. This modulator architecture has been introduced theoretically in [4][5][6][7].…”

“…Yet, it uses continuous time circuitry without switches or opamp settling constraints. In particular, building a band-pass CTSD modulator with the approach presented in this paper, benefits from the high Q factor of transmission lines, allows sub-sampling of the input [7], permits a fixed loop delay [5] and has a smaller clock jitter sensitivity than that of an equivalent CT solution [6]. Moreover, the I and Q paths of a quadrature SD modulator may be time multiplexed through a single loop filter if it is implemented with transmission lines [8], eliminating any mismatch.…”

A one-path subsampling quadrature receiver based on a ΣΔ modulator with distributed resonators

“…The TL based RDM is relatively insensitive to excess loop delay and clock jitter and can subsample, just like DT RD modulators. Moreover, the proposed RDM does not require a high-precision sampleand-hold nor switches and it is not limited by opamp settling constraints, just like traditional CT RDMs [8][9][10].…”