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AGC loop in 8347

Question asked by Orlando on Feb 10, 2017
Latest reply on Mar 9, 2017 by stanis

I am working on a GNSS (GPS and Galileo) RF-FE. I have found the AD8347 part which seems to be a fantastic Direct conversion Quadrature Demodulator. This part comes along with a baseband automatic gain control.  

 

Question 1 

My concern is whether the AD8347 is a good choice for GPS and Galileo signals which are very weak, below themal noise.

 

Question 2

The AD8347  has its own AGC loop. Will this AGC loop will also work with this kind of very weak signal below thermal noise? According t datasheet (page 17 of 28) "two signals proportional to the square of each output channel are summed together and compared to a built-in threshold". In my design it would have to work with the square of thermal noise in each I/Q channel.... 

 

BR

 

Orlando Peña

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