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dBm or dB mW (decibel-milliwatts) is a unit of power level expressed using a logarithmic decibel (dB) scale respective to one milliwatt (mW). It is commonly used by radio, microwave and fiber-optical communication technicians & engineers to measure the power of system transmissions on a log scale , which can express both very large and very ...
The decibel watt (dBW or dB W) is a unit for the measurement of the strength of a signal expressed in decibels relative to one watt.It is used because of its capability to express both very large and very small values of power in a short range of number; e.g., 1 milliwatt = −30 dBW, 1 watt = 0 dBW, 10 watts = 10 dBW, 100 watts = 20 dBW, and 1,000,000 W = 60 dBW.
High-powered transmissions, such as those used in broadcasting, are expressed in dB-millivolts per metre (dBmV/m). For very low-power systems, such as mobile phones , signal strength is usually expressed in dB - microvolts per metre (dBμV/m) or in decibels above a reference level of one milliwatt ( dBm ).
The decibel unit can also be combined with a reference level, often indicated via a suffix, to create an absolute unit of electric power. For example, it can be combined with "m" for "milliwatt" to produce the "dBm". A power level of 0 dBm corresponds to one milliwatt, and 1 dBm is one decibel greater (about 1.259 mW).
−13 dBm biomed: sound power incident on a human eardrum at the threshold intensity for pain (500 mW/m 2). 10 −3: milli-(mW) 1.55 × 10 −3: −4.7 dBm astro: power per square meter received from the Sun by Sedna at its aphelion 5 × 10 −3: 7 dBm tech: laser in a CD-ROM drive 5–10 × 10 −3: 7 dBm to 10 dBm tech: laser in a DVD player ...
The dBm is an absolute reference level measurement (see Decibel § Suffixes and reference values) with respect to 1 mW power. When the nominal signal power is 0 dBm at the TLP, the test point is called a zero transmission level point, or zero-dBm TLP. The abbreviation dBm0 stands for the power in dBm measured
In a second analysis, they also adjusted for medical factors, including hypertension, diabetes mellitus, APOE e4 allele (which increases dementia risk), body mass index (BMI), cholesterol levels ...
The decibel unloaded reference voltage, 0 dBu, is the AC voltage required to produce 1 mW of power across a 600 Ω impedance (approximately 0.7746 V RMS). [2] This awkward unit is a holdover from the early telephone standards, which used 600 Ω sources and loads, and measured dissipated power in decibel-milliwatts ( dBm ).