TopTechnical DictionarydBµV – logarithmic voltage unit

# dBµV – logarithmic voltage unit

 dBµV – absolute level unit relative to 1 µV (microvolt). The unit is commonly used in the radio, DVB-T and satellite technology.
 Example:satellite signal meter, DVB-T signal meter: input level range in dBµV,antenna amplifiers and multi-switches: input and output level range in dBµV.
 The unit expressed in dBµV indicates how much lower or higher the voltage is relative to 1µV. 0 dBµV corresponds to 1 µV (microvolt).
 The following voltage equation is used to convert µV into dBµV:
 U(ref) – reference value, i.e. reference unit, in this case 1 µV
 To simplify, the equation for voltage in dBµV is:
 Example:Converting 11.22 µV into dBµV.
 The following equation is used to convert dBµV into µV:
 Example:Converting 51 dBµV into µV (microvolts).

Table 1. Converting signal level from dBµV to voltage in µV and mV

 Signal level in dBµV Voltage in µV Voltage in mV 0 1 0,001 3 1,413 0,014125 6 1,995 0,0019953 9 2,818 0,0028184 12 3,981 0,0039811 15 5,623 0,0056234 18 7,943 0,0079433 21 11,220 0,011 24 15,849 0,016 27 22,387 0,022 30 31,623 0,032 33 44,668 0,045 36 63,096 0,063 39 89,125 0,089 42 125,893 0,126 45 177,828 0,178 48 251,189 0,251 51 354,813 0,355 54 501,187 0,501 57 707,946 0,708 60 1000 1 63 1412,538 1,413 66 1995,262 1,995 69 2818,383 2,818 72 3981,072 3,981 75 5623,413 5,623 78 7943,282 7,943 81 11220,185 11,220 84 15848,932 15,849 87 22387,211 22,387 90 31622,777 31,623 93 44668,359 44,668 96 63095,734 63,096 99 89125,094 89,125 102 125892,541 125,893 105 177827,941 177,828 108 251188,643 251,189 111 354813,389 354,813 114 501187,234 501,187 117 707945,784 707,946 120 1000000 1000

 The voltage can be easily converted into power: dBµV and dBmV to dBm. However, the internal impedance must be known to convert power to voltage. DVB-T, cable or industrial television systems use 75 Ohm impedance. Radio systems use 50 Ohm impedance.
 Equations for those two environments are given below:
 dBm = dBµV – 106,98 (@ 50 ohm)dBm = dBµV – 108,75 (@ 75 ohm)
 Example:Converting 70 dBµV to dBm (at 75 Ohm)
 dBm = 70 – 108,75 = –38,75 dBm
 dBm = dBmV – 46,9897 (@ 50 ohm)dBm = dBmV – 48,7506 (@ 75 ohm)
 Example:Converting 60 dBmV to dBm (at 75 Ohm).
 dBm = 60 – 48,7506 = 11,2494 dBm,
 which is approx. 11.25 dBm.
 Relationship between dBmV and dBµV:
 dBmV = dBµV – 60