Improved switched-capacitor interpolators with reduced sample-and-hold effects

This paper proposes improved switched-capacitor (SC) interpolators using a novel sampling technique which eliminates the undesired distortion due to t he sample-and-hold shaping effect Lit the lower input sampling rate. Such a sampling technique not only leads to a precise analog interpolation, as it s digital counterpart does, but also allows to simplify the design procedur es and resulting SC circuit implementations. Different circuit topologies w ith both finite- and infinite-impulse response characteristics are develope d, respectively, for low- and high-selectivity filtering, Practical impleme ntation issues are discussed with respect to capacitance ratio mismatches, as well as finite gain, bandwidth, and offset sensitivity effects of operat ional amplifiers. Besides detailed computer-based analyses, experimental re sults obtained from discrete component prototypes are also presented to dem onstrate the proposed circuits.