learn.howToCalculate
learn.whatIsHeading
Converts between power ratios and decibel scale for audio, RF, and other applications. Logarithmic scale matches human perception.
Wzór
dBm = 10 × log10(P ÷ 0.001)
- P
- P value — Variable used in the calculation
Przewodnik krok po kroku
- 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
Rozwiązane przykłady
Wejście
Power 1W
Wynik
30 dBm
Częste błędy do unikania
- ✕Confusing dBm (power) with dBV (voltage) with dBu (relative to 0.775V)
- ✕Adding dBm values instead of multiplying power
Często zadawane pytania
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.
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