About dBm Conversion

What is dBm?

dBm (decibel-milliwatts) is a unit used to measure power in radio, microwave, and fiber-optic communication systems. It represents power ratio in decibels (dB) of the measured power referenced to one milliwatt (mW).

Formulas for dBm Conversion

The formulas to convert between dBm, Watts, and milliwatts are:

1. dBm to Watts: \(P_{W} = 10^{\frac{P_{dBm} - 30}{10}}\)
2. Watts to dBm: \(P_{dBm} = 10 \log_{10}(P_{W} \times 1000)\)
3. dBm to milliwatts: \(P_{mW} = 10^{\frac{P_{dBm}}{10}}\)
4. milliwatts to dBm: \(P_{dBm} = 10 \log_{10}(P_{mW})\)

Where:

• \(P_{W}\) is the power in Watts
• \(P_{dBm}\) is the power in decibel-milliwatts
• \(P_{mW}\) is the power in milliwatts

Calculation Steps

1. Identify the power level in dBm.
2. To convert to Watts:
   • Subtract 30 from the dBm value.
   • Divide the result by 10.
   • Calculate 10 raised to the power of this result.
3. To convert to milliwatts:
   • Divide the dBm value by 10.
   • Calculate 10 raised to the power of this result.

Example

Let's convert 20 dBm to Watts and milliwatts:

1. Given: \(P_{dBm} = 20\)
2. To Watts:
   \(P_{W} = 10^{\frac{20 - 30}{10}} = 10^{-1} = 0.1\) Watts
3. To milliwatts:
   \(P_{mW} = 10^{\frac{20}{10}} = 10^2 = 100\) milliwatts

Visual representation:

Therefore, 20 dBm is equivalent to 0.1 Watts or 100 milliwatts.