SNDR
signal-to-noise and distortion ratio
Signal-to-noise and distortion ratio (SNDR) is a term used for a set of measures of the quality of a signal from a communications device. These include SINAD and SINADR.
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
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{\displaystyle \mathrm {SINAD} =10\log _{10}{\frac {P_{\text{signal}}+P_{\text{noise}}+P_{\text{distortion}}}{P_{\text{noise}}+P_{\text{distortion}}}},}
where
P
{\displaystyle P}
is the average power of the signal, noise and distortion components. The noise power term can include both thermal noise and quantization noise. 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.
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.
Begin with the source’s own compact description: “SNDR” is signal-to-noise and distortion ratio. The dossier treats that line as a proposition to test through SNDR, signal-to-noise and distortion, not as a finished interpretation.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Apr 16, 2025. The linked authority identifier is Q1470110. None of the 0 selected statements returned an explicit reference.
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This entry incorporates text from “SNDR” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.