 Top Tekninen sanakirja dBm - tehonmittauksen logarytmiyksikkö  # dBm - tehonmittauksen logarytmiyksikkö

 dBm – a unit of absolute level of reference to the power of 1 mW (milliwatt); a dBmW expression ought to be used according to the rule but the expression of dBm is exceptionally used here.
 This unit is commonly used in telecommunications (e.g. an output power of an access point is provided) or it is used in designing WLAN network. A unit expressed in dB informs us how much this power is lower than power expressed in 1 mW. The level 0 dB corresponds to 1 mW (milliwatt).
 A commonly used power formula is used in converting mW into dBm. P(ref) – a referential value, which is a reference measure, which in this case is 1 mW (milliwatt)
 A power formula in dBm which is more straightforward visually: ExampleLet us convert 10 mW into dBm: If we want to convert dBm into mW, we use the following formula: ExampleLet us convert 20 dBm into mW (milliwatts). Tab. 1. Conversion of dBm into mW - wide range

 -30 dBm 0,001 mW -20 dBm 0,01 mW -10 dBm 0,1 mW 0 dBm 1 mW 10 dBm 10 mW 20 dBm 100 mW 30 dBm 1000 mW 40 dBm 10000 mW 50 dBm 100000 mW 60 dBm 1000000 mW 70 dBm 10000000 mW 80 dBm 100000000 mW

Tab. 2. Conversion of dBm into mW - detailed range

 14 dBm 25,119 mW 16 dBm 39,811 mW 18 dBm 63,096 mW 20 dBm 100,000 mW 22 dBm 158,489 mW 24 dBm 251,189 mW 26 dBm 398,107 mW 28 dBm 630,957 mW 30 dBm 1000,000 mW

 We can also convert power to voltage very easily: dBm into dBµV and dBmV. In order to convert voltage from power we have to know internal impedance. In terrestrial, cable and industrial television systems, impedance of 75 ohm is used. In radio systems it is 50 ohm.
 The formulas for these two environments are provided below:
 dBmV = 46,9897 + dBm (@ 50 ohm)dBmV = 48,7506 + dBm (@ 75 ohm)
 ExampleWe convert 15 dBm into dBmV (for impedance of 50 ohm)
 dBmV = 46,9897 + 15 = 61,9897 dBmV
 dBµV = 60 + dBmV
 dBµV = 106,98 + dBm (@ 50 ohm)dBµV = 108,75 + dBm (@ 75 ohm)
 ExampleWe convert 20 dBm into dBµV (for impedance of 50 ohm)
 dBµV = 106,98 + 20 = 126,98 dBµV