lock-in amplifier AD630

Discussion in 'The Projects Forum' started by przemmo, Jan 11, 2009.

  1. przemmo

    Thread Starter New Member

    Jan 6, 2009
    8
    0
    I want to use this part to detect low fluorescence over the human skin surface. Has anyone worked with the modulator/demodulator? Will I meet any problem?
    For example simple circuit from the application note of AD630 (please find the jpeg)? I want to replace the bridge and instr. apm. with a light-to-voltage transducer with a gain stage. Do I need any phase shifter to adapt the phase of the gain stage to the reference generator signal?
     
  2. przemmo

    Thread Starter New Member

    Jan 6, 2009
    8
    0
    Why no answer? Did I write something stupid?
     
  3. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,575
    230
    Perhaps you could post the schematic of the front end you want to add. Otherwise, it's impossible to determine if a specific circuit creates a phase inversion problem. The more information you provide, the more likely you are to get a practical answer.

    Ken
     
  4. przemmo

    Thread Starter New Member

    Jan 6, 2009
    8
    0
    Phase inversion is one phase shift is something other. What I want to ask is if I have to tune the phase of the signal to the phase of generator used. Every amplifier, even cables creates some phase shift. I want to know if this is a problem or it's neglegible shift. The front end is just a photodiode with transimpedance amplifier (feedback resistor say 10-50Mohms) connected to the AD630.
     
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