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

Faizan Ul Haq*, Mikko Englund, Kim B. Östman, Kari Stadius, Marko Kosunen, Kimmo Koli, Jussi Ryynänen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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.

Original languageEnglish
Pages (from-to)1893-1906
JournalInternational Journal of Circuit Theory and Applications
Volume47
Issue number12
Early online date1 Jan 2019
DOIs
Publication statusPublished - Dec 2019
MoE publication typeA1 Journal article-refereed

Keywords

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

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