Computationally Efficient Synchronous Demodulation using Sigma-Delta Approach

Leis, John (2020) Computationally Efficient Synchronous Demodulation using Sigma-Delta Approach. In: 14th International Conference on Signal Processing and Communication Systems (ICSPCS 2020), 14-16 Dec 2020, Adelaide, Australia.


Abstract

Synchronous detection is an approach used to detect very low level signals within noise when the excitation signal is precisely known or generated locally. In the instrumentation and measurement field, this is generally termed lockin detection and the instrument is a lockin amplifier. A direct implementation samples the measured signal to the required precision, and then applies the lockin algorithm to the data in order to recover an estimate of the measured parameter. The mixing inherent in the lockin requires multiplication as well as filtering. In this paper, we propose dispensing with the full analog to digital conversion prior to analysis. The proposed method operates directly in the digital domain, with both filtering and synchronous averaging performed using oversampled bilevel signals. It is further shown that the required computation can be performed recursively and without the requirement for multiplication. The recursive calculation is exact, and no approximations are involved. This enables lower complexity hardware and permits operation in resource constrained devices where arithmetic, especially floating-point, is unavailable.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering (1 Jul 2013 -)
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering (1 Jul 2013 -)
Date Deposited: 03 Feb 2021 03:22
Last Modified: 17 Feb 2021 04:31
Uncontrolled Keywords: synchronous demodulation, lockin amplifier, sigma-delta converter
Fields of Research (2008): 09 Engineering > 0906 Electrical and Electronic Engineering > 090603 Industrial Electronics
09 Engineering > 0906 Electrical and Electronic Engineering > 090609 Signal Processing
09 Engineering > 0906 Electrical and Electronic Engineering > 090601 Circuits and Systems
Fields of Research (2020): 40 ENGINEERING > 4009 Electronics, sensors and digital hardware > 400903 Digital processor architectures
Socio-Economic Objectives (2008): E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
E Expanding Knowledge > 97 Expanding Knowledge > 970110 Expanding Knowledge in Technology
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280110 Expanding knowledge in engineering
Identification Number or DOI: https://doi.org/10.1109/ICSPCS50536.2020.9310036
URI: http://eprints.usq.edu.au/id/eprint/39934

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