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