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SBAS308A− MAY 2004 − REVISED MARCH 2005
Total Harmonic Distortion (THD)
THD is the ratio of the power of the fundamental (P ) to
the power of the first eight harmonics (P ).
Two-Tone Intermodulation Distortion
IMD3 is the ratio of the power of the fundamental (at
frequencies f and f ) to the power of the worst spectral
S
D
1
2
component at either frequency 2f −f or 2f −f . IMD3 is
1
2
2 1
PS
THD + 10Log
10 PD
either given in units of dBc (dB to carrier) when the
absolute power of the fundamental is used as the
reference, or dBFS (dB to Full-Scale) when the power
of the fundamental is extrapolated to the converter’s
full-scale range.
THD is typically given in units of dBc (dB to carrier).
Spurious-Free Dynamic Range (SFDR)
The ratio of the power of the fundamental to the highest
other spectral component (either spur or harmonic).
SFDR is typically given in units of dBc (dB to carrier).
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BB [ BURR-BROWN CORPORATION ]
