I began to learn the knowledge of AGC from this article"DESIGN AND OPERATION OF UTOMATIC GAIN CONTROL LOOPS FOR RECEIVERS IN MODERN COMMUNICATIONS SYSTEMS".

I can hardly understand the concept of "the incremental gains of the VGA".

i have copied the content on the following:

from the datasheet of AD8367, 20*log(Vout/Vin)= 50*(Vg-0.1)

how 0.6447Vrms/V came out(where did Vin go)? what does it mean??

if any one can help that would be apprecaite!

Best Regards

The missing mathematical equations are:

Combining the above equations:

Differentiating Vout with respect to Vg:

Multiplying by 112mV rms equilibrium value:

0.6447 Vrms/V