View source for Spurious-free dynamic range

'''Spurious-free dynamic range''' ('''SFDR''') is the strength ratio of the fundamental signal to the strongest spurious signal in the output. It
is also defined as a measure used to specify [[Analog-to-digital converter|analog-to-digital]] and [[digital-to-analog converter]]s (ADCs and DACs, respectively) and radio receivers.
SFDR is defined as the ratio of the [[Root Mean Square|RMS]] value of the [[carrier wave]] (maximum signal component) at the input of the ADC or output of DAC to the RMS value of the next largest [[Electronic noise|noise]] or [[harmonic distortion]] component (which is referred to as “'''spurious'''” or a “'''spur'''”) at its output. SFDR is usually measured in [[dBc]] (i.e. with respect to the [[carrier signal]] amplitude) or in [[dBFS]] (i.e. with respect to the ADC's [[Full scale|full-scale range]]). Depending on the test condition, SFDR is observed within a pre-defined frequency window or from [[Direct current|DC]] up to [[Nyquist frequency]] of the converter (ADC or DAC).
<ref>Walt Kester, [https://www.analog.com/media/en/training-seminars/tutorials/MT-003.pdf MT-003: Understand SINAD, ENOB, SNR, THD, THD + N, and SFDR so You Don't Get Lost in the Noise Floor], ''Analog Devices'', Retrieved 26 July 2011</ref>
In case of a radio receiver application, the definition is slightly different. The reference is the [[minimum detectable signal]] level at the input of a receiver, which can be calculated through a knowledge of the [[noise figure]] and the input signal [[Bandwidth (signal processing)|bandwidth]] of the receiver or the system.  The difference between this value and the input level which will produce distortion products equal to the minimum detectable signal referred to the input of the system is the SFDR of the system. However, this procedure is mainly reliable for [[Analog-to-digital converter|ADC]]s. In [[RF]] systems where output spurious signals are nonlinear function of input power, more precise measurement is required to take into account this non-linearity in power.
<math>DR_f(dB)=\tfrac{2}{3}(P_3-N_0)</math><ref>{{Cite book|title = Microwave and RF Design of Wireless Systems|last = Pozar|first = David M.|publisher = Wiley|year = 2001|isbn = 9780471322825|pages = 103,104|author-link=David M. Pozar}}</ref>
Where <math>P_3</math> is the [[third-order intercept point]] and <math>N_0</math> is the noise floor of the component, expressed in dB or dBm.
==References==
{{reflist}}
== See also ==
* [[Analog-to-digital converter]]
* [[Digital-to-analog converter]]
* [[Total harmonic distortion|THD]] (Total Harmonic Distortion)
* [[SINAD]] (Signal-to-Noise-And-Distortion)
[[Category:Digital signal processing]]
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