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

\mathrm {SINAD} =10\log _{10}{\frac {P_{\text{signal}}+P_{\text{noise}}+P_{\text{distortion}}}{P_{\text{noise}}+P_{\text{distortion}}}},

where $P$ 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:

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]
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 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]

^ 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)
^ "What is SINAD | SINAD Measurements | Electronics Notes". electronics-notes.com. Retrieved 24 March 2019.
^ "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.
^ "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.
^ 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

[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

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