Net Power: Difference between revisions

Revision as of 13:40, 13 June 2008

Net Power defined as Forward Power minus the Reflected Power This document describes how you should calculate the Net Power correctly.

**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.

${\displaystyle 50\$ ${\displaystyle 30\$

Subtract the linear values

$Net\ Power=Fw-Rf=100-1=99\ W$

Convert the value to dBm again:

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

@@ Line 1: / Line 1: @@
 [[Net Power]] defined as [[Forward Power]] minus the [[Reflected Power]]
-This document describes how you should calculate the [[Net power]] correctly.
+This document describes how you should calculate the [[Net Power]] correctly.
 {| border=1
@@ Line 14: / Line 14: @@
 '''Question:''' What is the Net Power?
-'''Answer:''' 141,8144768 mA
+'''Answer:''' 49,95635195 dBm
 == The calculation ==
-First you calculate the dB difference in power.
+First you calculate the dBm values to linear values.
-<math>35,4 - 35,1 = 0,3\ dB</math>
+<math> 50 \ dBm = 10^{\frac{50}{10}} \ mW = 100\ W</math>
+<math> 30 \ dBm = 10^{\frac{30}{10}} \ mW = 1\ W</math>
-*'''Note:''' the unit is dB not dBm
+Subtract the linear values
+<math> Net \ Power = Fw - Rf = 100 - 1 = 99 \ W</math>
-Calculate the calibrated current to dBmA so we can add the value.
+Convert the value to dBm again:
-<math>20 * log10(137) \approx  42,73441134 \ dBmA</math>
+<math>10 * log10(99 * 1000) \approx  49,95635195 \ dBm</math>
-So after the addition of the power difference the new value is 43,03441134 dBmA.
-Calculate this back to mA:
-<math>10^{\frac{43,03441134}{20}} \approx  141,8144768 \ mA</math>
 [[Category:RadiMation]]
 [[Category:Calculation]]