MiscEl: dB

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dB conversion

Voltage dB

VoltVoltage
dBVdB when using 1 volt as reference
dBmVdB when using 1 millivolt as reference
dbVdB when using 1 microvolt as reference
dBxxdB when using the values, specified in the reference box, as reference
dB50dB when using 1 milliWatt in 50ohm, (223milliVolt) as reference, this is also sometimes called dBm
dB600dB when using 1 milliWatt in 600ohm, (775milliVolt) as reference, this is also sometimes called dBu, dBm or dBv

Power dB

WattWatt
dBwdb when using 1 watt as reference
dBmWdb when using 1 milliwatt as reference
dBWdb when using 1 microwatt as reference
dBxxdB when using the power, specified in the reference box, as reference
VxxdB when using the values, specified in the reference box, as reference
V50Volts over 50ohms
V600Volts over 600ohms

Factors

Factor
dB power10*log(factor)
dB voltage20*log(factor)
Np powerNeper
Np voltage Neper

Octaves/decades

dB/octoctave is 2
dB/decdecade is 10

Reference

ImpedanceReference impedance
PowerReference power
VoltageReference voltage (Reference impedance is used to convert between power and voltage)

Calculator functions

The Calculator has some dB functions:
todB(times) todBpwr(timesPower) fromdB(dB) fromdBpwr(dB)