The dBm (sometimes also dBmW or decibel-milliwatt) is a unit of measurement of power expressed in decibels (dB) relative to one milliwatt (mW). It is used in radio networks, microwave and optical fiber as a convenient measure of absolute power because of their ability to express both very large and very small values ??in short form. It is distinct from dBW, which refers to one watt (mW 1,000). Typical values:

• 21 DBM-> 125 MW> Maximum output power for a mobile phone UMTS/3G (phone power class 4).
• 15 DBM-> 32 MW> Typical power transmission WiFi laptops.
• 0 DBM-> 1.0 mW = 1000 ?W-> Standard Bluetooth Class 3 coverage 1m.
• DBM- -10> 100 ?W-> Typically the maximum Potentiometeria that can be received on a wireless network (-10 to -30 dBm).
• -194 DBM-> 0.00004 AW-> thermal noise bandwidth of 1 Hz in outer space (4 kelvin).

It is normally used dBm optical fiber, external radio networks, microwave. This measure, which also can be called dBmW is a measure that is in decibels relative to one milliwatt. The main idea is to measure dBm power factors.

One hertz is one cycle per second, meaning repeating cycle as an event. For example, hertz is applied physics measuring the number of times for a second wave (either acoustic or electromagnetic) is repeated or can be applied, among other uses, to ocean waves that reach the Beach vibrations per second or a solid. The quantity that measures the frequency hertz is called,in this regard, the inverse of the period. One hertz is an oscillation frequency of suffering a particle over a period of one second.