STA321 Datasheet, PDF (154/157 Pages) STMicroelectronics – 4-channel digital audio system with FFX™ driver

Glossary
17 Glossary
STA321
Total harmonic distortion + noise (THDN)
The ratio of the RMS value of all the spectral components in the specified band (20 Hz -
20 kHz) to the RMS values of the signal fundamental component. THDN is measured at
0 dBfs input at a frequency of 1 kHz.
Signal to noise plus distortion ratio (SNDR)
Ratio between power of signal fundamental component and “noise+distortion”. It is
measured at different input levels: 0 dBfs, -3 dBfs, -6 dBfs, -10 dBfs, -20 dBfs, -40 dBfs,
-60 dBfs. When the signal amplitude is less than 0 dBfs, that much dB is added to obtain the
final SNR. For example, if SNDR is 87 dB with -6dBfs signal, then SNR = 87 + 6 = 93 dB.
Dynamic range (DR)
Dynamic range is measured using SNDR at -60 dBfs, 1 kHz signal and adding 60 dB. For
example, if SNDR with -60 dBfs is 38 dB then the dynamic range is 38 + 60 = 98 dB.
Crosstalk
Crosstalk is the measure of the inter-channel isolation between the left and right channels of
a stereo system. It is measured at each output with zero input to the channel under test and
a full-scale input applied to the other channel.
Deviation from linear phase
Measurement bandwidth 20 Hz to 20 kHz, f_S = 48 kHz. The measurement takes into
account the combined digital and analog filter characteristics.
Pass band, pass-band ripple, stop band, stop-band attenuation
These parameters take into account both analog and digital filter characteristics. Stop-band
attenuation should be measured between 0.55 * f_S and 3.45 * f_S.
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Doc ID 15351 Rev 3