The decibel watt (dBW or dB
W) is a unit for the measurement of the strength of a signal expressed in
decibel
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a po ...
s relative to one
watt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wa ...
. 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.
:
and also
:
Compare dBW to
dBm
DBM or dbm may refer to:
Science and technology
* dBm, a unit for power measurement
* DBM (computing), family of key-value database engines including dbm, ndbm, gdbm, and Berkeley DB
* Database Manager (DBM), a component of 1987's ''Extended Edi ...
, which is referenced to one milliwatt (0.001 W).
A given dBW value expressed in dBm is always 30 more because 1 watt is 1,000 milliwatts, and a ratio of 1,000 (in power) is 30 dB; e.g., 10 dBm (10 mW) is equal to −20 dBW (0.01 W).
In the
SI system the non SI modifier
decibel
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a po ...
(dB) is not permitted for use directly alongside
SI units so the dBW is not directly permitted but 10 dBW may be written 10 dB (1 watt).
See also
*
dBm
DBM or dbm may refer to:
Science and technology
* dBm, a unit for power measurement
* DBM (computing), family of key-value database engines including dbm, ndbm, gdbm, and Berkeley DB
* Database Manager (DBM), a component of 1987's ''Extended Edi ...
References
Sound
Units of power
Logarithmic scales of measurement
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