TY - JOUR
T1 - DDFS and ΣΔ Approaches for Fractional Frequency Synthesis in Terahertz Instruments
AU - Tang, Adrian
AU - Kim, Yanghyo
AU - Reck, Theodore J.
AU - Chattopadhyay, Goutam
AU - Mehdi, Imran
AU - Drouin, Brian J.
AU - Cooper, Ken B.
AU - Livesey, Nathaniel J.
AU - Chang, Mau Chung Frank
N1 - Publisher Copyright:
© 2011-2012 IEEE.
PY - 2018/7
Y1 - 2018/7
N2 - This paper compares direct digital frequency synthesis (DDFS) and ΣΔ CMOS-based frequency synthesizers for terahertz instrument systems. This paper first discusses the need for fractional synthesis in terahertz systems, and provides a brief overview of reference clock frequency selection, and design choices related to implementation of fractional functionality. ΣΔ-multistage-noise-shape-based and DDFS-based fractional synthesis approaches and architectures are discussed and CMOS synthesizer modules based on both of these approaches are presented. Finally, the paper compares two different 100-GHz CMOS fractional frequency synthesizer chips, which employ the same millimeter-wave circuits but different fractional generators (third- and sixth-order ΣΔ, and DDFS-based). Performance in terms of phase-noise, spurious components, and power consumption are directly compared. Measurements suggest ΣΔ synthesis is more suitable than DDFS for THz fractional synthesizers due to the high-phase multiplication of spurs.
AB - This paper compares direct digital frequency synthesis (DDFS) and ΣΔ CMOS-based frequency synthesizers for terahertz instrument systems. This paper first discusses the need for fractional synthesis in terahertz systems, and provides a brief overview of reference clock frequency selection, and design choices related to implementation of fractional functionality. ΣΔ-multistage-noise-shape-based and DDFS-based fractional synthesis approaches and architectures are discussed and CMOS synthesizer modules based on both of these approaches are presented. Finally, the paper compares two different 100-GHz CMOS fractional frequency synthesizer chips, which employ the same millimeter-wave circuits but different fractional generators (third- and sixth-order ΣΔ, and DDFS-based). Performance in terms of phase-noise, spurious components, and power consumption are directly compared. Measurements suggest ΣΔ synthesis is more suitable than DDFS for THz fractional synthesizers due to the high-phase multiplication of spurs.
KW - CMOS
KW - fractional synthesizer
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U2 - 10.1109/TTHZ.2018.2840078
DO - 10.1109/TTHZ.2018.2840078
M3 - Article
AN - SCOPUS:85047637959
SN - 2156-342X
VL - 8
SP - 410
EP - 417
JO - IEEE Transactions on Terahertz Science and Technology
JF - IEEE Transactions on Terahertz Science and Technology
IS - 4
ER -