Spurious-free dynamic range: Difference between revisions
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'''Spurious-free dynamic range''' ('''SFDR''') is the strength ratio of the fundamental signal to the strongest spurious signal in the output. It |
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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. |
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SFDR is defined as the ratio of the [[Root Mean Square|RMS]] value of the [[ |
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). |
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<ref>Walt Kester, [ |
<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> |
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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 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. |
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<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> |
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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. |
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==References== |
==References== |
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* [[Digital-to-analog converter]] |
* [[Digital-to-analog converter]] |
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* [[Total harmonic distortion|THD]] (Total Harmonic Distortion) |
* [[Total harmonic distortion|THD]] (Total Harmonic Distortion) |
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* [[SINAD]] ( |
* [[SINAD]] (Signal-to-Noise-And-Distortion) |
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[[Category:Digital signal processing]] |
[[Category:Digital signal processing]] |
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Latest revision as of 09:54, 26 September 2024
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 and digital-to-analog converters (ADCs and DACs, respectively) and radio receivers.
SFDR is defined as the ratio of the 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 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 range). Depending on the test condition, SFDR is observed within a pre-defined frequency window or from DC up to Nyquist frequency of the converter (ADC or DAC). [1]
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 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 ADCs. 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.
Where is the third-order intercept point and is the noise floor of the component, expressed in dB or dBm.
References
[edit]- ^ Walt Kester, 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
- ^ Pozar, David M. (2001). Microwave and RF Design of Wireless Systems. Wiley. pp. 103, 104. ISBN 9780471322825.
See also
[edit]- Analog-to-digital converter
- Digital-to-analog converter
- THD (Total Harmonic Distortion)
- SINAD (Signal-to-Noise-And-Distortion)
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