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AM demodulation of low power signal (-110dBm)

Question asked by doom on Nov 22, 2010
Latest reply on Feb 4, 2011 by doom



First, I want to say that I am a newbie in RF/IF.


I want to make an AM demodulation of a low power signal which power range is from -110dBm to -30dBm approximatively.

The carrier is from 50MHz to 400MHz, and the bandwidth around the carrier is about 50kHz.

The aim of the RF circuit is to translate the carriered signal to baseband (best for me) or to very low IF freq as 200kHz (which seems to be more easy).

Another function is to know the power of the signal.

After, just entering to an ADC and µP.


I see that AD8348 seems to be suitable for my design as it seems to translate input signal directly to baseband.


I want to know  if you think that AD8348 is suitable for this application or if another AD chip is better ?

Do you know if there is somewhere something that looks like my project ?


Where should I put the additionnal amplifier : before or after the AD8348 ? (AD8348 has a 44dB VGA)


Thank you for your answer.