A.H. Systems AK-285R, Руководство по эксплуатации

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A.H. Systems AK-285R Shielding Effectiveness Antenna Kit
TYPICAL CONVERSION FORMULAS
LOG -> LINEAR VOLTAGE FIELD STRENGTH & POWER DENSITY
dB
µ
V to Volts V = 10 ((dB
µ
V – 120) / 20) dB
µ
V/m to V/m
V/m = 10
(((dB
µ
V/m) -120) / 20)
Volts to dB
µ
V dB
µ
V = 20 log(V) + 120 V/m to dB
µ
V/m dB
µ
V/m = 20 log(V/m) + 120
dBV to Volts V = 10 (dBV / 20)
dB
µ
V/m to dBmW/m 2 dBmW/m 2 = dB
µ
V/m – 115.8
Volts to dBV dBV = 20log(V)
dBmW/m 2 to dB
µ
V/m dB
µ
V/m = dBmW/m 2 + 115.8
dBV to dB
µ
V dB
µ
V = dBV +120 dB
µ
V/m to dB
µ
A/m dB
µ
A/m = dB
µ
V/m – 51.5
dB
µ
V to dBV dBV = dB
µ
V - 120 dB
µ
A/m to dB
µ
V/m dB
µ
V/m = dB
µ
A + 51.5
LOG -> LINEAR CURRENT
dB
µ
A/m to dBpT DBpT = dB
µ
A/m + 2
dB
µ
A to uA
µ
A = 10 (dB
µ
A / 20) dBpT to dB
µ
A/m dB
µ
A/m = dBpT – 2
µ
A to dB
µ
A dB
µ
A = 20 log(
µ
A)
W/m 2 to V/m V/m = SQRT(W/m 2 * 377)
dBA to A A = 10 (dBA / 20) V/m to W/m 2 W/m 2 = (V/m) 2 / 377
A to dBA dBA = 20log(A) µ
T to A/m A/m =
µ
T / 1.25
dBA to dB
µ
A dB
µ
A = dBA + 120 A/m to
µ
T
µ
T = 1.25 * A/m
dB
µ
A to dBA dBA = dB
µ
A -120
E-FIELD ANTENNAS
LOG -> LINEAR POWER Correction Factor
dB
µ
V/m = dB
µ
V + AF
dBm to Watts W = 10 ((dBm – 30)/10) Field Strength V/m = 30 * watts * Gain
numeric
meters
Watts to dBm dBm = 10log(W) + 30 Required Power Watts = (V/m * meters) 2
30 * Gain
numeric
dBW to Watts W = 10 (dBW / 10) LOOP ANTENNAS
Watts to dBW dBW = 10log(W) Correction Factors
dB
µ
A/m = dB
µ
V + AF
dBW to dBm dBm = dBW + 30 Assumed E-field for
shielded loops
dB
µ
V/m = dB
µ
A/m + 51.5
dBm to dBW dBW = dBm - 30
dBpT = dB
µ
V + dBpT/
µ
V
TERM CONVERSIONS
dBm to dB
µ
V
dB
µ
V =
dBm + 107
(50
Ω
)
dB
µ
V = dBm + 10log(Z) + 90
CURRENT PROBES
dB
µ
V to dBm dBm = dB
µ
V – 107
(50
Ω
)
dBm = dB
µ
V – 10log(Z) – 90
Correction Factor
dB
µ
A = dB
µ
V – dB
(ohm)
dBm to dB
µ
A dB
µ
A = dBm – 73
(50
Ω
)
dB
µ
A = dBm – 10log(Z) + 90
Power needed for injection probe given voltage(V) into
50
Ω
load and Probe Insertion Loss (I
L
)
dB
µ
A to dBm dBm = dB
µ
A + 73
(50
Ω
)
dBm = dB
µ
A + 10log(Z) – 90
Watts = 10
((I
L
+ 10log(V 2 /50))/10)
dB
µ
A to dB
µ
V dB
µ
V = dB
µ
A + 34
(50
Ω
)
dB
µ
V = dB
µ
A + 20log(Z)
dB
µ
V to dB
µ
A dB
µ
A = dB
µ
V – 34
(50
Ω
)
dB
µ
A = dB
µ
V – 20log(Z)

A.H. Systems inc. – August 2011
REV A
14