circuit design to measure signal level variation ?

I want to be able to get accurate measurements of the variations in signal
strength of a signal over time.

The signal of interest is amplified, and the amp includes AGC. The
attenuation level of the AGC circuit is logarithmically related to a current
output from the AGC circuit.

I am thinking that I need to do the following:

Convert the AGC current to a voltage that represents Attenuation. The Maxim
MAX4206 Log Amp is a readily available IC that I think will handle this
function.

I would then convert the Output Signal to DC, convert it to log, and add it
to the AGC voltage obtained above.

Am I overlooking anything?

Is there a simpler or better way?

Scott Kelley


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