Difference between revisions of "Net Power"

Revision as of 20:15, 20 January 2009

Net Power is defined as Forward Power minus the Reflected Power. This document describes the formula's that should be used to correctly calculate the Net Power.

**Given information**
Frequency [MHz]	Forward Power [dBm]	Reflected Power [dBm]
201,973	50	30

Question: What is the Net Power?

Answer: 49,95635195 dBm

First you calculate the dBm values to linear values.

$50\ dBm=10^{\frac {50}{10}}\ mW=100\ W$

Formula -1: Logarithmic power value to linear power value

$30\ dBm=10^{\frac {30}{10}}\ mW=1\ W$

Subtract the linear values

$P_{net}=P_{fwd}[W]-P_{refl}[W]=100[W]-1[W]=99\ W$

Formula -2: Net power calculation from forward and reflected power

Convert the value to dBm again:

$10*log10(99*1000)\approx 49,95635195\ dBm$

Formula -3: Linear power value to logarithmic power value

@@ Line 19: / Line 19: @@
 <math> 50 \ dBm = 10^{\frac{50}{10}} \ mW = 100\ W</math>
+{{Formula||1|Logarithmic power value to linear power value}}
 <math> 30 \ dBm = 10^{\frac{30}{10}} \ mW = 1\ W</math>
@@ Line 24: / Line 26: @@
 Subtract the linear values
-<math> Net \ Power = Fw - Rf = 100 - 1 = 99 \ W</math>
+<math>P_{net} = P_{fwd}[W] - P_{refl}[W] = 100 [W] - 1 [W] = 99 \ W</math>
+{{Formula||2|Net power calculation from forward and reflected power}}
 Convert the value to dBm again:
 <math>10 * log10(99 * 1000) \approx  49,95635195 \ dBm</math>
+{{Formula||3|Linear power value to logarithmic power value}}
 [[Category:RadiMation]]
 [[Category:Calculation]]