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Creating a two-phase lock-in-amplifier using the AD630

Question asked by analoged on Jan 22, 2017
Latest reply on Jan 23, 2017 by jstaley

Hi,

I would like to use a two-phase lock-in amplifier to find the magnitude and phase of a signal using a reference signal and a 90 degree phase shifted signal (full description on the  lock-in wiki page). 

If I use the AD630 to demodulate the signal I'm not sure what the inputs into pin 9 and 10 should be on the second de-modulator (de-modulator with the out of phase signal). I think the 90 degrees out of phase signal goes to pin 9, and pin 10 is tied to ground.  

The lock in amplifiers have  AD8429's before the de-modulator and a low pass filter after. The schematic for the de-modulator is attached.

Is this right? Will this pin arrangement give me a two-phase lock-in amplifier?

Out of interest are there any other analog IC's that can achieve the same thing?

Thanks,

Ed 

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