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We derive a method for using distributed resonators in AS modulators and demonstrate these AS modulators have several advantages over existing AS modulator architectures. Like continuous-time (CT) [DELTA] [SIGMA] modulators, the proposed [DELTA] [SIGMA] modulators do not require a high-precision track-and-hold, and additionally can take advantage of the high-Q of distributed resonators. Like discrete-time [DELTA] [SIGMA] modulators, the proposed [DELTA] [SIGMA] modulators are relatively insensitive to feedback loop delays and can subsample. We present simulations of several types of these [DELTA] [SIGMA] modulators and examine the challenges in their design. Index Terms--Analog-to-digital conversion, continuous-time (CT) systems, sigma--delta modulation, transmission line resonators.

Recent advancement in superconducting microwave technology has led to commercial deployment of high-temperature superconducting (HTS) subsystems for wireless communication applications. Commercialization of the HTS thin-film devices lies within, among other factors, the quality and consistency of the HTS film, as well as the overall cost and performance of the subsystem. In this paper, we present the design and performance of a quasi-lumped element filter on sapphire substrate. Centered at 1857 MHz with 0.8% fractional bandwidth, the six-pole Chebyshev filter has an insertion loss of less than 0.2 dB at 60 K, which translates into a realized unload Q of 35000. This is an important step toward the commercialization of superconducting devices using industrial standard wafers. With the continuous improvement of the HTS film quality, YBCO film on sapphire could be an answer to the future. Index Terms - Applied superconducting, planar filter, sapphire, superconducting filter.