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RF amplifier , testing, conversions and distance for EUT

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qu1nn

Electrical
Feb 8, 2003
18
US
I think that I got my self confused in the units, and I am kind of new with this so you will have to bear with me....

----------Goal----------
To rent test equipment in order to perform immunity tests similar to IEC 61000-4-3
(3V/m, 26Mhz to 1GHz, 1kHz sine +/- 80%) to work out any bugs before the device goes for official testing.

-------Layout--------------
Signal Generator ---> RF Amplifier ---> Antenna


---- my logic/questions --------------
Typically the Generator has a RF output of about 13dBm ( if my conversions are correct this is equivalent to 0.02W or 120dBuV )

Since the EUT test requires a level of 3V/m ( if my conversions are again correct this is equal to 9.5dBv or 129.5dBuV)

How do I calculate what size amplifier I need along with the distance requirement?


My guess is that at the output of the signal generator I could obtain a maximum of 1V...neglecting antenna gain/loss if I were to move 1m away from the signal generator my power would be cut in half or 0.01W which would now have a signal strength of 117dBuV, or 0.71V/m. Thus if I want a level of 3V/m at say 1m so I would want an output of 6V/m or 135.5dBuV ???

Also if a an RF amplifier says that it will provide 20dB of gain... how do I calculate what the total output power?
is it just 13dBm + 20dB = 33dB ???

If I am a couple of meters away and there is free air propagation, how much free air loss can I expect?



Thanks for your time
Qu1nn



Qu1nn
 
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Recommended for you

Suggestion: Visit
for:
EN 50082-1: "New Approach" generic European standard that provides radiated immunity field levels for electronic apparatus intended for use in residential, commercial, and light industrial environments. Calls out IEC 801-3 as the basic testing document to be used.

EN 50082-2: "New Approach" generic European standard that provides radiated immunity field levels for electronic apparatus intended for use in the heavy industrial environment. Calls out IEC 1000-4-3 as the basic testing document to be used.

etc. for more info

The following equation:
13dBm + 20dB = 33dB ???
has to have the same dimensions on the left side and on the right side.
 
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