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device ratings mentioned in dbm and Volts

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microwave dbm to volts

How can I convert the device ratings mentioned in volts to dbm and viceversa for microwave components

I'll appreciate if someone can provide some material on this topic.
 

Volts are units for potential difference. dBm or dB over mW (miliwatt) are units for power. You can't convert V to dBm, these are two different things!

You can do it if you are referring to a constant R:

P = V^2/R
R is const. and you have P in V, but that's not realy correct. Sometimes it is said Power of x dBV with R=y ohm.
 

radiohead said:
Good old minicircuits :D

h**p://www.minicircuits.com/dg03-110.pdf
Click to expand...

Yes, that is my second point. But be carefull, this is for R=50 ohm, for any other R you must do the calculations.
 

The answer is both simple and complicated.

IF you are in a 50 ohm system, the power is simply P=(Vrms²)/50 in Watts, and that power in dBm (ie dB referenced to 1 milliwatt) is Pdbm=10 log P = 10 Log [(Vrms²)/(50*1000)].

However, there are many systems that do not use a 50 ohm characteristic impedance. A differential radio front end that connects to an antenna could be any impedance, and then a maximum voltage is a more meaningful limit to specify.
 

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