A multistage closed-loop sigma-delta modulator (MSCL)
Analog Integrated Circuits and Signal Processing
A Methodology for Designing Continuous-Time Sigma-Delta Modulators
EDTC '97 Proceedings of the 1997 European conference on Design and Test
A self-calibration scheme for extended frequency-band-decomposition sigma-delta ADC
Analog Integrated Circuits and Signal Processing
4- and 6-GS/s 4-bit frequency-translating hybrid ADCs in 90-nm CMOS
Analog Integrated Circuits and Signal Processing
A new interpolation technique for time interleaved $$\Upsigma\Updelta$$ A/D converters
Analog Integrated Circuits and Signal Processing
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Parallelism can be used to increase the bandwidths of ADC converters based on sigma---delta modulators. Each modulator converts a part of the input signal band and is followed by a digital filter. Unfortunately, solutions using bandpass sigma---delta modulators are very sensitive to the position of the modulators' central frequencies. This paper shows the feasibility of a frequency-band-decomposition (FBD) ADC using continuous time bandpass sigma---delta modulators, even in the case of large analog mismatches. The major benefit of such a solution, called extended-frequency-band-decomposition (EFBD) is its low sensitivity to analog parameters. For example, a relative error in the central frequencies of 4% can be accepted without significant degradation in the performance (other published FBD ADCs require a precision of the central frequencies better than 0.1%). This paper will focus on the performance which can be reached with this system, and the architecture of the digital part. The quantization of coefficients and operators will be addressed. It will be shown that a 14 bit resolution can be theoretically reached using 10 sixth-order bandpass modulators at a sampling frequency of 800 MHz which results in a bandwidth of 80 MHz centered around 200 MHz (the resolution depends on the effective quality factor of the filters of the analog modulators).