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Converts between power ratios and decibel scale for audio, RF, and other applications. Logarithmic scale matches human perception.
Công thức
dBm = 10 × log10(P ÷ 0.001)
- P
- P value — Variable used in the calculation
Hướng dẫn từng bước
- 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
Ví dụ có lời giải
đầu vào
Power 1W
Kết quả
30 dBm
Lỗi thường gặp cần tránh
- ✕Confusing dBm (power) with dBV (voltage) with dBu (relative to 0.775V)
- ✕Adding dBm values instead of multiplying power
Câu hỏi thường gặp
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.
Sẵn sàng để tính toán? Dùng thử Máy tính Decibelm W miễn phí
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