dBm calculator - conversion voltage V to dB dBu dBV dBm mW power level power watts kilo watt convertor converter - sengpielaudio Checker
 
Deutsche Version UK-flag s/w - sengpielaudio D-flag - sengpielaudio
 
• Conversion: Voltage V to Level  dB, dBu, dBV, and dBm •

Usually we measure AC voltage V as voltsRMS.

Voltage V:  volts (Root Mean Square RMS)
     
         ↓         
     
Voltage level L:  
L =  dBu reference: 0.775 V
L =  dBV reference: 1 V
Power level L: Not used for audio!
L =  dBm > > >   ref. 1 mW at ohms
The index u at decibel (dB) means unloaded source, V (volt). Some say: The "u" in dBu
implies also that the load impedance is unspecified, or unterminated and is likely to be high.
The index m at dB (decibel) means 1 milliwatt (power) as reference value for 0 dB.

If the reverse conversion dBu, or dBV to volts is needed, go to the converter at the bottom.

• What is dBu?
A logarithmic voltage ratio with a reference voltage of V0= 0.7746 volt ≡ 0 dBu

• What is dBV?
A logarithmic voltage ratio with a reference voltage of V0 = 1.0000 volt ≡ 0 dBV
The max. home recording level of −10 dBV means 0.3162 volts, that is −7.78 dBu

Level   Formula volt to level        Voltage   Formula level to volt

Rainbow line

• What is dBm?
A logarithmic ratio with a reference power of P0 = 1.000 milliwatt ≡ 0 dBm.
The dBm is not used in audio engineering. With the known impedance value you
can convert voltage V to level dBm (power) and vice versa.

For radio frequency systems (RF), power matching or impedance matching
is absolutely essential.

• The dBm calculator for power matching
or impedance matching •

Not used in audio engineering.

Enter two values, the third value will be calculated.
Voltage V, level L, and impedance Z

Voltage V   V RMS
 Power level L   dBm re 1 mW 
Impedance Z   Ω
 

dBm indicates that the reference power is P0 = 1 milliwatt = 0.001 watt ≡ 0 dB

Enter a value in the left or right box, then press the TAB bar or make
a mouse click at an empty space at the side, to get the solution.
The calculator works in both directions of the ↔ sign.

Electric power (phone) P:
watts		  ↔  Electric Power level LP
dBm (phone)
Start   Start
Reference power P0 = 1 milliwatt (mW) = 0.001 W ≡ 0 dBm

Telephone lines need an input impedance and an
output impedance of 600 ohms for power matching.

Reference voltage at 600 ohms - 1 mW according to 0 dBm
weiter
Reference voltage at 50 Ohm - 1 mW according to 0 dBm
weiter

dBu is a voltage standard where "zero" (as in zero dB on your meters) is considered to be
0.775 volts and +4 dBu is therefore 1.23 volts. dBm is a power measurement (the "m" stands
for milliwatts), where +4 also happens to be 1.23 volts if the load impedance is 600 ohms.
In many cases (and this is "old school" audio) a 600 ohm load can be assumed, however,
in modern day interconnects input impedances are usually much higher, which kind of renders
the dBm standard useless. This is one reason why most gear is rated in dBu, or in dBV
(another voltage standard).

• Definition of dBm

dBm is defined as power ratio in decibel (dB) referenced to one milliwatt (mW). It is an
abbreviation for dB with respect to 1 mW and the "m" in dBm stands for milliwatt.

dBm is different from dB. dBm represents absolute power, whereas in audio engineering the
decibel is usually a voltage ratio of two values and is used then to represent gain or attenuation
of an audio amplifier, or an audio damping pad.

If you use modern audio equipment in sound engineering, above calculators used at
typically 600 ohms impedance for telephone lines or antennas, are of no value.
Matching impedance for power is not used anymore in the audio field.
You will only use voltage bridging or impedance bridging.

Here comes your adequate calculator for audio voltage and voltage levels:

Converter: Decibel to Voltage and vice versa

back zurück Search Engine weiter home start