learn.howToCalculate
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Converts between power ratios and decibel scale for audio, RF, and other applications. Logarithmic scale matches human perception.
Formel
dBm = 10 × log10(P ÷ 0.001)
- P
- P value — Variable used in the calculation
Steg-för-steg-guide
- 1dBm = 10 × log10(P ÷ 0.001)
- 2dBW = 10 × log10(P)
- 3Reverse: power (watts) = 10^(dBm ÷ 10) ÷ 1000
- 4Every 3 dB ≈ 2× power
- 5Every 10 dB ≈ 10× power
Lösta exempel
Ingång
Power 1W
Resultat
30 dBm
Vanliga misstag att undvika
- ✕Confusing dBm (power) with dBV (voltage) with dBu (relative to 0.775V)
- ✕Adding dBm values instead of multiplying power
Vanliga frågor
Why use decibels instead of watts?
Logarithmic scale compresses large ranges (1W to 1MW becomes 30 dBm to 60 dBm), easier comparison.
What's typical dBm for audio and RF?
Audio -20 to +4 dBu typical; WiFi transmit +17 to +30 dBm; cellular -30 to +33 dBm.
Redo att beräkna? Prova den kostnadsfria Decibelm W-kalkylatorn
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