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 language | English |
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Pages (from-to) | 1893-1906 |
Journal | International Journal of Circuit Theory and Applications |
Volume | 47 |
Issue number | 12 |
Early online date | 1 Jan 2019 |
DOIs | |
Publication status | Published - Dec 2019 |
MoE publication type | A1 Journal article-refereed |
Keywords
- direct ΔΣ receiver
- dynamic range
- N-path filter
- quantization noise
- \special t4ht@.<spispace>ΔΣ modulator