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What is a decibel?
The decibel is a standard unit for measuring relative levels of current, voltage, or power.
The decibel shows the ratio between the input and the output.
Decibel is abbreviated dB.
A minus sign before the dB indicates a loss and a plus sign or no sign at all before the dB indicates a gain.
The Decibel Formula
The decibel value of a change between input and output can be expressed utilizing the following algorithm:
db = log10 Input / Output
A Decibel Table
| Decibel Gain | Ratio of Gain |
|---|---|
| 1 | 1.3 |
| 3 | 2.0 |
| 5 | 3.2 |
| 6 | 4.0 |
| 7 | 5.0 |
| 10 | 10 |
| 20 | 100 |
| 30 | 1,000 |
| 40 | 10,000 |
| 50 | 100,000 |
| 60 | 1,000,000 |
From this table, we can see that a gain of 3dB doubles the signal. Similarly, a loss of -3dB reduces the signal strength by half.
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