一分贝(dB)表示单元信号强度的相对差异。其比率的基础对数为10,,如dB = 10 x Log10 (P1/P2)。

基础10对数规则:

对数系统中有如下运算:

1 mW

1 mW/1mW=1

0 dbm = 10 x Log10 (1)

2 mW

2 mW/1mW=2

3 dbm = 10 x Log10 (2)

4 mW

4 mW/1mW=4

6 dbm = 10 x Log10 (4)

10 mW

10 mW/1mW=10

10 dbm = 10 x Log10(10)

0.1 W

100 mW/1mW=100

20 dbm = 10 x Log10(100)

1W

1000 mW/1mW=1000

30 dbm = 10 x Log10 (1000)

10 W

10000mW/1mW=10000

40 dbm = 10 x Log10 (10000)

dbm = dB毫瓦特= 10 x Log10 (电源mW/1mW)

电源

比率

dbm = 10 x Log10 (电源在兆瓦mW/1mW)

1 mW

1 mW/1mW=1

0 dbm = 10 x Log10 (1)

2 mW

2 mW/1mW=2

3 dbm = 10 x Log10 (2)

4 mW

4 mW/1mW=4

6 dbm = 10 x Log10 (4)

10 mW

10 mW/1mW=10

10 dbm = 10 x Log10(10)

0.1 W

100 mW/1mW=100

20 dbm = 10 x Log10(100)

1W

1000 mW/1mW=1000

30 dbm = 10 x Log10 (1000)

10 W

10000mW/1mW=10000

40 dbm = 10 x Log10 (10000)

dbw = dB瓦特= 10 x Log10 (电源W/1W)

电源

比率

dbm = 10 x Log10 (电源W/1W)

1W

1与1 W = 1

0 dbw = 10 x Log10 (1)

2 W

2与1 W = 2

3 dbw = 10 x Log10 (2)

4 W

4与1 W = 4

6 dbw = 10 x Log10 (4)

10 W

10与1 W = 10

10 dbw = 10 x Log10(10)

100 W

0,1与1 W = 0,1

-10 dbw = -10 x Log10(10)

10 W

0,01与1 W = 1/100

-20 dbw = -10 x Log10(100)

1 W

0,001W/1W=1/1000

-30 dbw = -10 x Log10 (1000)

在射频信号中,0dBm=1mW,每3dB功率信号翻倍,每10dB功率信号变为10倍;对电压信号,则是每6dB电压信号翻倍,每20dB电压信号变为10倍

05-11 13:43