Calculateur de Résolution CNA
Calculez la résolution d'un convertisseur numérique-analogique.
THD
2.567 %
THD vs Fundamental Amplitude
Formule
## What is Total Harmonic Distortion? THD measures the ratio of harmonic content to the fundamental, indicating how much a device distorts a pure signal. ### Formula **THD = sqrt(V2^2 + V3^2 + V4^2 + V5^2 + ...) / V1 x 100%** Where V1 is the fundamental and V2, V3... are harmonic amplitudes. ### Quality Benchmarks - < 0.01%: Audiophile/measurement grade - 0.01-0.1%: High fidelity - 0.1-1%: Consumer electronics - > 1%: Noticeable distortion
Exemple Résolu
Fundamental at 1.0 V with harmonics at 0.02, 0.015, 0.005, 0.003 V.
- 01RSS = sqrt(0.02^2 + 0.015^2 + 0.005^2 + 0.003^2)
- 02= sqrt(0.0004 + 0.000225 + 0.000025 + 0.000009) = sqrt(0.000659)
- 03= 0.02567 V
- 04THD = 0.02567 / 1.0 x 100 = 2.567%
- 05THD dB = 20 x log10(0.02567) = -31.8 dB
Questions Fréquentes
Is THD the same as THD+N?
No. THD measures only harmonics. THD+N includes noise and all non-harmonic distortion, making it a more comprehensive metric.
Do higher harmonics matter less?
In audio, odd harmonics (3rd, 5th) are perceived as harsher than even harmonics (2nd, 4th). But in the THD formula, all are weighted equally by the RSS.
How many harmonics should I include?
Include at least the first 5 harmonics. For precision, include up to the 10th or until harmonics fall below the noise floor.
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