Search results
Results From The WOW.Com Content Network
In audio, 0 dBm often corresponds to approximately 0.775 volts, since 0.775 V dissipates 1 mW in a 600 Ω load. [16] The corresponding voltage level is 0 dBu, without the 600 Ω restriction. Conversely, for RF situations with a 50 Ω load, 0 dBm corresponds to approximately 0.224 volts, since 0.224 V dissipates 1 mW in a 50 Ω load.
The electric field strength at a specific point can be determined from the power delivered to the transmitting antenna, its geometry and radiation resistance. Consider the case of a center-fed half-wave dipole antenna in free space, where the total length L is equal to one half wavelength (λ/2).
For VHF bands the recommendation defines S9 to be a receiver input power of -93 dBm. This is the equivalent of 5 microvolts in 50 ohms. [6] The recommendation defines that a difference of one S-unit corresponds to a difference of 6 decibels (dB), equivalent to a voltage ratio of two, or power ratio of four.
A power level of 0 dBm corresponds to one milliwatt, and 1 dBm is one decibel greater (about 1.259 mW). In professional audio specifications, a popular unit is the dBu. This is relative to the root mean square voltage which delivers 1 mW (0 dBm) into a 600-ohm resistor, or √ 1 mW × 600 Ω ≈ 0.775 V RMS.
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 ).
A common voltage for medium-size electric lanterns. [19] A voltage for older electric systems of automobiles. Deca-10 1: 12 V Typical car battery [20] Hecto-10 2: 100–240 V Domestic wall socket voltage [21] 600 V Electric eel sends this voltage in an average attack 630 V London Underground railway tracks Kilo-10 3: 2450 V
TLP = dBm — dBm0. The term TLP is commonly used as if it were a unit, [2] preceded by the nominal level for the test point. For example, the expression 0 TLP refers to a 0 dBm TLP. If for instance a signal is specified as -13 dBm0 at a particular point and -6 dBm is measured at that point, the TLP is +7 TLP. [3]
dBV - voltage relative to 1 volt, regardless of impedance. Surely the impedance is only important when converting between dBm and dBu/dBV? Pediacycle 04:48, 14 August 2007 (UTC) Because the reference is a specific voltage, the actual *power* is most definitely dependent on the impedance. P=E^2 / R