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Low Pass filter Lock-in output to 16-bit ADC

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jonnybgood

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Attached is the output from a Lock-in amplifier simulation. I need to filter this out to DC for feeding it into a MAX1416 Sigma-Delta 16-bit ADC.

What factors should I consider? I planned to design a Sallen-Key LPF with some gain using an online calculator. Do you think the signal is too small to be filtered and amplified with a single stage 2nd Order LPF? Maybe I should have implemented some pre amplification at the earlier stages of the circuit like the high pass filter for example..

thanks
 

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  • vrect_to_filter.bmp
    771.5 KB · Views: 79
  • lockinohmeter.bmp
    790.9 KB · Views: 79

Maybe I should have implemented some pre amplification at the earlier stages of the circuit like the high pass filter for example..
Click to expand...
Surely.

If you worry about signal-to-noise ratio and switching spikes, you possibly also want to limit the AC signal bandwidth before feeding it to the demodulator.

Being around at edaboard for more than three years, that you ever hear that uncompressed bitmap images are unwanted?
 
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