A.H. Systems SAS-521-2 Manuale operativo - Pagina 13

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A.H. Systems SAS-521-2 Bilogical Antenna
LOG -> LINEAR VOLTAGE
dBµV to Volts
V = 10
Volts to dBµV
dBµV = 20 log(V) + 120
dBV to Volts
V = 10
Volts to dBV
dBV = 20log(V)
dBV to dBµV
dBµV = dBV +120
dBµV to dBV
dBV = dBµV - 120
LOG -> LINEAR CURRENT
µA = 10
dBµA to uA
µA to dBµA
dBµA = 20 log(µA)
dBA to A
A = 10
A to dBA
dBA = 20log(A)
dBA to dBµA
dBµA = dBA + 120
dBµA to dBA
dBA = dBµA -120
LOG -> LINEAR POWER
dBm to Watts
W = 10
Watts to dBm
dBm = 10log(W) + 30
dBW to Watts
W = 10
Watts to dBW
dBW = 10log(W)
dBW to dBm
dBm = dBW + 30
dBm to dBW
dBW = dBm - 30
TERM CONVERSIONS
dBm to dBµV
dB
dB µ V = dBm + 10log(Z) + 90
dBµV to dBm
dBm = dBµV – 107
dBm = dB µ V – 10log(Z) – 90
dBm to dBµA
dBµA = dBm – 73
dB µ A = dBm – 10log(Z) + 90
dBµA to dBm
dBm = dBµA + 73
dBm = dB µ A + 10log(Z) – 90
dBµA to dBµV
dBµV = dBµA + 34
dB µ V = dB µ A + 20log(Z)
dBµV to dBµA
dBµA = dBµV – 34
dB µ A = dB µ V – 20log(Z)
© A.H. Systems inc. – December 2008
REV C
TYPICAL CONVERSION FORMULAS
((dB µ V – 120) / 20)
(dBV / 20)
(dB µ A / 20)
(dBA / 20)
((dBm – 30)/10)
(dBW / 10)
µV =
dBm + 107
(50Ω)
(50Ω)
(50Ω)
(50Ω)
(50Ω)
(50Ω)
FIELD STRENGTH & POWER DENSITY
dBµV/m to V/m
V/m to dBµV/m
dBµV/m to dBmW/m
2
dBmW/m
2
to dBµV/m
dBµV/m to dBµA/m
dBµA/m to dBµV/m
dBµA/m to dBpT
dBpT to dBµA/m
2
W/m
to V/m
V/m to W/m
2
µT to A/m
A/m to µT
E-FIELD ANTENNAS
Correction Factor
Field Strength
Required Power
LOOP ANTENNAS
Correction Factors
Assumed E-field for
shielded loops
CURRENT PROBES
Correction Factor
Power needed for injection probe given voltage(V) into
50Ω load and Probe Insertion Loss (I
(((dB µ V/m) -120) / 20)
V/m =
10
dBµV/m = 20 log(V/m) + 120
dBmW/m
2
= dBµV/m – 115.8
dBµV/m = dBmW/m
2
+ 115.8
dBµA/m = dBµV/m – 51.5
dBµV/m = dBµA + 51.5
DBpT = dBµA/m + 2
dBµA/m = dBpT – 2
2
V/m = SQRT(W/m
* 377)
W/m
2
= (V/m)
2
/ 377
A/m = µT / 1.25
µT = 1.25 * A/m
µ
dBµV/m = dB
V + AF
V/m =
30 * watts * Gain
meters
Watts = (V/m * meters)
2
30 * Gain
numeric
dBµA/m = dBµV + AF
dBµV/m = dBµA/m + 51.5
dBpT = dBµV + dBpT/µV
dBµA = dBµV – dB
(ohm)
)
L
((I
+ 10log(V
2
/50))/10)
Watts = 10
L
numeric
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