Meaning of DB
Unitdb, or decibel, is a very common unit in the field of electronics. This unit is characterized by the use of logarithms to represent the original data.
1 shell = 10 db = 10dB = 10 times times Power
For an amplifier,power Magnification Ap = ten lg (PO/PI)voltage Magnification Au = LG (UO/UI)current Magnification Ai = LG (IO/II)
For example: amplifier magnification of 40dB, indicating that its voltage amplification is 100 times times, current amplification is 100 times times, so power amplification is 10,000 times times
Common DB Values
0dB = 1 time times power3dB is approximately twice times the power, in turn -3db about 0.5 times times the power10dB = 10 times times Power20dB = 100 times Times Power
benefits of using DB as a unit
It is convenient to represent a large range, 0dB = 1 time times power, 10dB = 10 times times power, and 80dB = 100,000,000 times power, -20db = 0.01 times times power.
You can convert the multiplication operation into an addition operation. For example, for a cascade amplifier, the three-stage power magnification is 10,100,1000, the total magnification is three, it is easy to calculate and write errors. But expressed in db form, respectively, 10db,20db,30db, the total magnification of 10+20+30=60db, convenient a lot.
It is because of the benefits that science and other fields such as electronics, such as seismic grade, sound size, and so on, are used in decibels or similar to the exponential representation of decibels.
DBMW/DBM/DB milli-watt
Unit decibel, writing DBMW or DBM, is a unit that represents power. The formula is x = 10LG (P/1MW), and the ratio of power to 1mW is expressed in db.
0dBm = 1mW
Each additional 3dBm represents a doubling of power and, in the same vein, reduces power by half per 3dBm.
This article by Purplesword (jzj1993) Original, reproduced please specify the original URL http://blog.csdn.net/jzj1993
The meaning and benefit of the unit db (decibel), the meaning of dBm (DBMW db milli-watt)
