Enter the original power of the signal and the reduction into the calculator to determine the power of the signal after a 3dB reduction.

3Db Rule Formula

The following formula is used to calculate the signal power after a 3dB reduction.

P2 = P1 / (10^{(3/10)})

Variables:

• P2 is the power of the signal after the 3dB reduction (Watts)
• P1 is the original power of the signal (Watts)

To calculate the power of the signal after a 3dB reduction, divide the original power of the signal by 10 raised to the power of 3 divided by 10. This formula is derived from the definition of decibel, which is a logarithmic unit used to express the ratio of two values of a physical quantity. In this case, a decrease of 3dB represents a halving of the signal’s power.

What is a 3Db Rule?

The 3dB rule is a standard rule in electronics and signal processing, stating that a signal has half its original power when its amplitude is reduced by approximately 30%. This is often used in the context of signal attenuation, bandwidth measurement, and frequency response, where a decrease of 3dB represents a halving of the signal’s power. The term “3dB” comes from the use of decibels (dB) as a logarithmic unit to express the ratio of two values of a physical quantity.

How to Calculate 3Db Rule?

The following steps outline how to calculate the 3dB Rule.

1. First, determine the original power of the signal (P1) in Watts.
2. Next, calculate the power of the signal after the 3dB reduction (P2) using the formula: P2 = P1 / (10^(3/10)).
3. Finally, calculate the 3dB Rule.
4. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem :

Use the following variables as an example problem to test your knowledge.

Original power of the signal (P1) = 100 Watts