Trivial problem but very difficult solution. I have to define a demodulator for an AM modulated signal. When a passive tag is excited with a sine wave of 134.200kHz (carrier of 3Vp-p) it send back a modulated signal and the level of signal is decreasing with 1/r^3 law, where r is the distance between the antenna and the tag. The depth of modulation is from 1% to 0,01% of amplitude of the carrier and the frequency of the signal of modulation is 4kHz.The difficult is to reach the distance of 40cm or more between the antenna and tag because the amplitude of demodulated signal is comparable with the noise. Now I'm analyzing the features of AD633 and I don't see an example of application to perform AM synchronous demodulation. I ask if someone has already used a AD633 to demodulate an AM signal. No answer to this question in the existing documentation.
Thanks in advance of your attention.
[edited by: Mausine at 11:17 AM (GMT -4) on 21 Jun 2021]