A 0.8–2 GHz Fully-Integrated QPLL-Timed Direct-RF-Sampling Bandpass $\Sigma \Delta$ ADC in 0.13 $\mu$m CMOS

Design and Evaluation of Frequency-Agile Multi-Standard Direct RF Digitizing Receivers for Automotive Use

“…In CT-domain this could be a resonator. Such a reconfigurable bandpass filter in CT, can be realized in g m -C technique or LC-filter based [8] and is able to respond to different signal positions. Here, we concentrate on the LC-filter model which can be realized practically e.g.…”

“…Here, we concentrate on the LC-filter model which can be realized practically e.g. with on-chip inductors [8]. It would be both power efficient and area efficient for the GHz range application in CMOS technology.…”

“…This transformation holds for notch frequencies at f n = f s /4. In a more general case with a reconfigurable notch frequency the transfer function [8] in DT is…”

“…Besides the potential increase in flexibility due to undersampling, an impairment of the ADC's SQNR occurs, as the quantization noise of each Nyquist zone is additively overlying within the first Nyquist zone. [8] states an approximate value of 3 − 5 dB per Nyquist zone.…”

On the use of passive circuits to implement LC-based band-pass CT ΣΔ modulators

“…These ADCs benefit from the combined action of noise-shaping and oversampling techniques, with the feasible operation of CT circuits in the GHz range, in order to digitize Radio-Frequency (RF) signals in standard CMOS technologies [1]- [3].…”