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Power meter in end of transmitter

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JesperJ

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Hi

I'm trying to make a RF circuit based on two si4713 (fm radio transmitter) that is combined into one signal, that signal is then amplified through a 7W amplifier. I have tested this circuit and it works. However I would like to measure the output power from the amplifier and build a variable gain preamp, so that I will be able to regulate the output power 1-7W from a microcontroller. Can anyone recommend a way to do this?

system.png

7W : **broken link removed**
 

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A directional coupler or SWR bridge is the preferred method to measure forward and reflected power.
 

Don't use Variable Gain Amplifier, instead use a Programmable Attenuator.( There are tons of such attenuators in the market..)Because VGA will disturb the signal with its own nonlinearity.
Also, use a Directional Coupler OR a RF Power Detector IC ( look at Analog Devices or similar mfg.) to measure accurately the RF Power then you can control RF Power by adjusting Programmable RF Attenuator
 
That made a lot of sense :) Thank you for leading me in that direction
 

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