Performance and characterization of the SPT-3G digital frequency-domain multiplexed readout system using an improved noise and crosstalk model

Joshua Montgomery, Peter A.R. Ade, Zeeshan Ahmed, Ethan Anderes, Adam J. Anderson, Melanie Archipley, Jessica S. Avva, Kevin Aylor, Lennart Balkenhol, Peter S. Barry, Ritoban B. Thakur, Karim Benabed, Amy N. Bender, Bradford A. Benson, Federico Bianchini, Lindsey E. Bleem, Francois R. Bouchet, Lincoln Bryant, Karen Byrum, John E. CarlstromFaustin W. Carter, Thomas W. Cecil, Clarence L. Chang, Prakrut Chaubal, Geoffrey Chen, Hsiaomei Cho, Ti Lin Chou, Jean Francois Cliche, Tom M. Crawford, Ari Cukierman, Cail Daley, Tijmen De Haan, Edward V. Denison, Karia Dibert, Junjia Ding, Matt A. Dobbs, Daniel Dutcher, Tucker Elleflot, Wendeline Everett, Cahng Feng, Kyle R. Ferguson, Allen Foster, Jianyang Fu, Silvia Galli, Anne E. Gambrel, Robert W. Gardner, Neil Goeckner-Wald, John C. Groh, Riccardo Gualtieri, Sam Guns, Nikhel Gupta, Robert Guyser, Nils W. Halverson, Angelina H. Harke-Hosemann, Nicholas L. Harrington, Jason W. Henning, Gene C. Hilton, Eric Hivon, William L. Holzapfel, John C. Hood, Doug Howe, Nicholas Huang, Kent D. Irwin, Oliver B. Jeong, Michelle Jonas, Adam Jones, Trupti S. Khaire, Lloyd Knox, Anna M. Kofman, Milo Korman, Donna L. Kubik, Stephen Kuhlmann, Chao Lin Kuo, Adrian T. Lee, Erik M. Leitch, Amy E. Lowitz, Chunyu Lu, Stephan S. Meyer, Daniel Michalik, Marius Millea, Andrew Nadolski, Tyler Natoli, Hogan Nguyen, Gavin I. Noble, Valentine Novosad, Yuuki Omori, Steve Padin, Zhaodi Pan, Pascal Paschos, John Pearson, Chrystian M. Posada, Karthik Prabhu, Wei Quan, Alexandra Rahlin, Christian L. Reichardt, David Riebel, Benedikt Riedel, MacLean Rouble, John E. Ruhl, James T. Sayre, Eduardo Schiappucci, Erik Shirokoff, Graeme Smecher, Joshua A. Sobrin, Antony A. Stark, Judith Stephen, Kyle T. Story, Aritoki Suzuki, Keith L. Thompson, Ben Thorne, Carole Tucker, Caterina Umilta, Leila R. Vale, Keith Vanderlinde, Joaquin D. Vieira, Gensheng Wang, Nathan Whitehorn, Wai L.K. Wu, Volodymyr Yefremenko, Ki W. Yoon, Matt R. Young

Research output: Contribution to journalArticlepeer-review


The third-generation South Pole Telescope camera (SPT-3G) improves upon its predecessor (SPTpol) by an order of magnitude increase in detectors on the focal plane. The technology used to read out and control these detectors, digital frequency-domain multiplexing (DfMUX), is conceptually the same as used for SPTpol, but extended to accommodate more detectors. A nearly 5× expansion in the readout operating bandwidth has enabled the use of this large focal plane, and SPT-3G performance meets the forecasting targets relevant to its science objectives. However, the electrical dynamics of the higher-bandwidth readout differ from predictions based on models of the SPTpol system due to the higher frequencies used and parasitic impedances associated with new cryogenic electronic architecture. To address this, we present an updated derivation for electrical crosstalk in higher-bandwidth DfMUX systems and identify two previously uncharacterized contributions to readout noise, which become dominant at high bias frequency. The updated crosstalk and noise models successfully describe the measured crosstalk and readout noise performance of SPT-3G. These results also suggest specific changes to warm electronics component values, wire-harness properties, and SQUID parameters, to improve the readout system for future experiments using DfMUX, such as the LiteBIRD space telescope.

Original languageEnglish (US)
Article number014001
JournalJournal of Astronomical Telescopes, Instruments, and Systems
Issue number1
StatePublished - Jan 1 2022


  • cosmic microwave background instrumentation
  • crosstalk
  • digital frequency-domain multiplexing
  • frequency-domain multiplexing
  • readout noise
  • third-generation South Pole Telescope camera

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Control and Systems Engineering
  • Instrumentation
  • Astronomy and Astrophysics
  • Mechanical Engineering
  • Space and Planetary Science


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