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26.7 V, dBµV, dBmV and dBm conversion
dBµV (dBmV) is a logarithmic ratio between a measured voltage Ud and a reference voltage Ur.
The reference voltage is Ur = 1 μV (1 mV)
N = 20 log (Ud/Ur)
dBm is a logarithmic ratio between a measured power Pd and a reference power Pr.
The reference power is Pr = 1 mW into 75 ohms.
N = 10 log (Pd/Pr) with Pd = Ud2 / 75
U
d
= 1 µV
N = 0 dBµV
N = - 60 dBmV
N = -108.75 dBm
U
d
= 1 mV
N = 60 dBµV
N = 0 dBmV
N = -48.75 dBm
U
d
= 1 V
N = 120 dBµV
N = 60 dBmV
N = 11.25 dBm
26.8 Typical values for measurements
Values given are indicatives, minimum and maximum for good signal quality
Measurements
Level, power (dBµV)
C/N
(dB)
BER
MER
(dB)
modulation
mini
maxi
Terrestrial
Analogue TV
57
74
> 45
-
-
-
FM
50
66
> 38
-
-
-
DAB/DAB+
35
70
BER < 2
E
-4
-
2K
DVB-T/H
35
70
> 26
VBER < 2
E
-4
> 26
8K, 64QAM, 1/32, 2/3
DVB-T2
35
70
> 22
FER < 2
E
-7
> 22
32K, 256QAM, 1/8, 2/3
DVB-C
57
74
> 31
BER < 2
E
-4
> 31
64QAM
Satellite
Analogue TV
47
77
> 15
-
-
-
DVB-S, DSS
47
77
> 11
VBER < 2
E
-4
> 11
QPSK, 3/4
DVB-S2
47
77
> 8
PER < 1
E
-7
> 8
8PSK, 2/3
