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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
= 1 µV
d
U
= 1 mV
d
U
= 1 V
d
26.8
Typical values for measurements
Values given are indicatives, minimum and maximum for good signal quality
Measurements
Terrestrial
Analogue TV
FM
DAB/DAB+
DVB-T/H
DVB-T2
DVB-C
Satellite
Analogue TV
DVB-S, DSS
DVB-S2
– MCT059 –
N = 0 dBµV
N = 60 dBµV
N = 120 dBµV
Level, power (dBµV)
mini
maxi
57
74
50
66
35
70
35
70
35
70
57
74
47
77
47
77
47
77
N = - 60 dBmV
N = 0 dBmV
N = 60 dBmV
C/N
BER
(dB)
> 45
-
> 38
-
E
BER < 2
-4
E
> 26
VBER < 2
-4
E
> 22
FER < 2
-7
E
> 31
BER < 2
-4
> 15
-
> 11
VBER < 2
E
-4
E
> 8
PER < 1
-7
p.
100
N = -108.75 dBm
N = -48.75 dBm
N = 11.25 dBm
MER
modulation
(dB)
-
-
-
> 26
8K, 64QAM, 1/32, 2/3
> 22
32K, 256QAM, 1/8, 2/3
> 31
64QAM
-
> 11
QPSK, 3/4
> 8
8PSK, 2/3
-
-
2K
-
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