TYPICAL CONVERSION FORMULAS

[Pages:6]TYPICAL CONVERSION FORMULAS

LOG -> LINEAR VOLTAGE

FIELD STRENGTH & POWER DENSITY

dB?V to Volts

V = 10 ((dB?V ? 120) / 20)

Volts to dB?V dBV to Volts

dB?V = 20 log(V) + 120 V = 10 (dBV / 20)

Volts to dBV

dBV = 20log(V)

dBV to dB?V

dB?V = dBV +120

dB?V to dBV

dBV = dB?V - 120

LOG -> LINEAR CURRENT

dB?A to uA

?A = 10 (dB?A / 20)

?A to dB?A dBA to A

dB?A = 20 log(?A) A = 10 (dBA / 20)

dB?V/m to V/m V/m to dB?V/m dB?V/m to dBmW/m2 dBmW/m2 to dB?V/m dB?V/m to dB?A/m dB?A/m to dB?V/m dB?A/m to dBpT dBpT to dB?A/m W/m2 to V/m V/m to W/m2

V/m = 10 (((dB?V/m) -120) / 20)

dB?V/m = 20 log(V/m) + 120 dBmW/m2 = dB?V/m ? 115.8 dB?V/m = dBmW/m2 + 115.8 dB?A/m = dB?V/m ? 51.5 dB?V/m = dB?A + 51.5 DBpT = dB?A/m + 2 dB?A/m = dBpT ? 2 V/m = SQRT(W/m2 * 377) W/m2 = (V/m)2 / 377

A to dBA

dBA = 20log(A)

dBA to dB?A

dB?A = dBA + 120

dB?A to dBA

dBA = dB?A -120

LOG -> LINEAR POWER

dBm to Watts

W = 10((dBm ? 30)/10)

Watts to dBm

dBm = 10log(W) + 30

dBW to Watts

W = 10(dBW / 10)

?T to A/m

A/m = ?T / 1.25

A/m to ?T

?T = 1.25 * A/m

E-FIELD ANTENNAS

Correction Factor Field Strength

Required Power

dB?V/m = dB?V + AF

V/m = 30 * watts * Gain numeric meters

Watts = (V/m * meters)2 30 * Gain numeric

Watts to dBW

dBW = 10log(W)

LOOP ANTENNAS

dBW to dBm dBm to dBW

dBm = dBW + 30 dBW = dBm - 30

TERM CONVERSIONS

dBm to dB?V

dB?V = dBm + 107 (50) dB?V = dBm + 10log(Z) + 90

dB?V to dBm

dBm = dB?V ? 107 (50) dBm = dB?V ? 10log(Z) ? 90

Correction Factors

Assumed E-field for shielded loops

dB?A/m = dB?V + AF dB?V/m = dB?A/m + 51.5

dBpT = dB?V + dBpT/?V

CURRENT PROBES

Correction Factor

dB?A = dB?V ? dB(ohm)

dBm to dB?A

dB?A = dBm + 73 (50) dB?A = dBm ? 10log(Z) + 90

Power needed for injection probe given voltage(V) into 50 load and Probe Insertion Loss (IL)

dB?A to dBm

dBm = dB?A ? 73 (50) dBm = dB?A + 10log(Z) ? 90

Watts = 10 ((IL + 10log(V2/50))/10)

dB?A to dB?V

dB?V = dB?A + 34 (50) dB?V = dB?A + 20log(Z)

dB?V to dB?A

dB?A = dB?V ? 34 (50) dB?A = dB?V ? 20log(Z)

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