Quantization noise upconversion effects in mixer-first direct delta-sigma receivers

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2019-12

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Mcode

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Language

en

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International Journal of Circuit Theory and Applications, Volume 47, issue 12, pp. 1893-1906

Abstract

In this paper, we investigate the application of the direct ΔΣ receiver (DDSR) concept in a mixer-first architecture. Specifically, we analyze the degrading effects of quantization noise (Qn) upconversion on DDSR sensitivity, which is a major concern in mixer-first DDSR architecture. We demonstrate that with the chosen approach, the mixer-first architecture is suitable for the DDSR despite the potential challenges arising from Qn upconversion. A systematic modeling and understanding of Qn upconversion effects is presented, which lead to simple design guidelines. The results demonstrate that a first-order low-pass Qn filtering is sufficient in most cases for mixer-first DDSR implementations. Based on analytical results, we design a transistor-level mixer-first DDSR by merging the functionality of N-path capacitors both as channel select and Qn filters. Simulations performed in a 28-nm complementary metal-oxideŰsemiconductor (CMOS) process show a mere 1.5-dB degradation from maximum signal-to-noise and distortion ratio (SNDR) for the worst-case scenarios arising from Qn upconversion effects, validating the chosen approach.

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Keywords

direct ΔΣ receiver, dynamic range, N-path filter, quantization noise, \special t4ht@.<spispace>ΔΣ modulator

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Citation

Ul Haq, F, Englund, M, Östman, K B, Stadius, K, Kosunen, M, Koli, K & Ryynänen, J 2019, ' Quantization noise upconversion effects in mixer-first direct delta-sigma receivers ', International Journal of Circuit Theory and Applications, vol. 47, no. 12, pp. 1893-1906 . https://doi.org/10.1002/cta.2705