Calculateur de Fréquence de Nyquist
Calculez la fréquence de Nyquist pour l'échantillonnage numérique.
Return Loss
10.88 dB
Reflection Coefficient0.2857
Power Reflected8.16 %
Power Delivered91.84 %
Mismatch Loss0.370 dB
Return Loss vs VSWR
Formule
Understanding Return Loss
Return loss measures how much signal is reflected due to impedance mismatch, expressed in positive decibels (higher is better).
Formulas
Gamma = (VSWR - 1) / (VSWR + 1)
Return Loss = -20 x log10(Gamma) dB
Mismatch Loss = -10 x log10(1 - Gamma^2) dB
Quick Reference
Exemple Résolu
A cable assembly has VSWR 1.8:1.
- 01Gamma = (1.8 - 1) / (1.8 + 1) = 0.8 / 2.8 = 0.2857
- 02Return loss: -20 x log10(0.2857) = 10.88 dB
- 03Power reflected: 0.2857^2 x 100 = 8.16%
- 04Power delivered: 91.84%
- 05Mismatch loss: -10 x log10(0.9184) = 0.370 dB
Questions Fréquentes
Is higher return loss better?
Yes. Higher return loss (in dB) means less reflection. A perfect match has infinite return loss.
What is the minimum acceptable return loss?
Typically 10 dB (VSWR 1.92) for most systems. High-performance systems require 15-20 dB or better.
How is return loss measured?
Using a vector network analyzer (VNA) that measures the S11 parameter of the device under test.
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