SINAD

The signal-to-noise and distortion ratio (SINAD) is a measure of the quality of a signal from a communications device, often defined as

where is the average power of the signal, noise and distortion components. SINAD is usually expressed in dB and is quoted alongside the receiver RF sensitivity, to give a quantitative evaluation of the receiver sensitivity. Note that with this definition, unlike SNR, a SINAD reading can never be less than 1 (i.e. it is always positive when quoted in dB).

When calculating the distortion, it is common to exclude the DC components.[1]

Due to widespread use, SINAD has collected several different definitions. SINAD is commonly defined as:

  1. The ratio of (a) total received power, i.e., the signal to (b) the noise-plus-distortion power. This is modeled by the equation above.[2]
  2. The ratio of (a) the power of a test signal, i.e. a sine wave, to (b) the residual received power, i.e. noise-plus-distortion power. With this definition, it is possible to have a SINAD level less than one. This definition is used in the calculation of effective number of bits (ENOB) for DACs[3] and ADCs.[4]

Information on the relations between SINAD, ENOB, SNR, THD and SFDR can be found in the footnotes of this article.[5]

  1. ^ Tutorial 740 : Glossary of Frequently Used High-Speed Data Converter Terms (PDF), Maxim Integrated, 17 December 2001, retrieved 25 April 2021 {{citation}}: External link in |format= (help)
  2. ^ "What is SINAD | SINAD Measurements | Electronics Notes". electronics-notes.com. Retrieved 24 March 2019.
  3. ^ "IEEE Standard for Terminology and Test Methods of Digital-to-Analog Converter Devices". IEEE STD 1658-2011: 1–126. 1 February 2012. doi:10.1109/IEEESTD.2012.6152113. ISBN 978-0-7381-7147-0.
  4. ^ "IEEE Standard for Terminology and Test Methods for Analog-to-Digital Converters". IEEE STD 1241-2010 (Revision of IEEE STD 1241-2000): 1–139. 1 January 2011. doi:10.1109/IEEESTD.2011.5692956. ISBN 978-0-7381-6239-3.
  5. ^ Kester, Walt (October 2008), Understand SINAD, ENOB, SNR, THD, THD + N, and SFDR so You Don't Get Lost in the Noise Floor (PDF), MT-003, Analog Devices, Inc., archived (PDF) from the original on 9 October 2022, retrieved 25 April 2021