What is the concept of 40db noise reduction?

The concept of 40db noise reduction refers to reducing the noise by 40 decibels, which means that the noise has been reduced to a certain extent; and dB is actually a ratio, a numerical value, and a pure counting method without any unit label. Different fields have different names, so it also represents different practical meanings.

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What is the concept of 40db noise reduction?

40db noise reduction: refers to the concept of reducing noise by 40 decibels. This shows that the noise has been reduced to a certain extent.

DB (Decibel)

dB is a ratio, a numerical value, a pure counting method without any unit label.

has different names in different fields, so it also represents different practical meanings.

Decibel meaning

1. Relative intensity

In electromagnetics, dB is defined as the ratio of the intensity of a certain quantity to the reference intensity. When multiplying a number by 10, db is not a unit, but a numerical value used to express a ratio.

Common expression: dB

2. Signal strength

In the field of wireless communications, measuring the communication signal strength of a certain wireless base station in a location can also be expressed in dB. For example, the measured communication signal strength of No. 1 wireless base station in Room 402 of a hotel is -90dBm, which is defined here as the useful signal strength (signal power) of the room.

Common expressions: dBm, dBw

3, gain

In terms of antenna technology, dB is a parameter that measures antenna performance, and its name is gain. It refers to the ratio of the power density of the signal generated by the actual antenna and the ideal antenna at the same point in space under the condition that the input power is equal.

Common representations: dBi, dBd

4. Meaning in other fields

In the field of electronic engineering, the amplifier gain is dB. The ratio of the amplifier output to the input is the amplification factor, and the unit is "times", such as a 10x amplifier and a 100x amplifier. When "decibels" is used as the unit, the amplification factor is called gain, which are two names for the same concept.

The conversion relationship between decibels and magnification in electricity is:

A(V)(dB)=20lg(Vo/Vi)；电压增益
A(I)(dB)=20lg(Io/Ii)；电流增益
A(p)(dB)=10lg(Po/Pi)；功率增益

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