Hi Vasanth, Thanks for the updates. Let me address a few points first: 1. To convert Volts to Magnitude (dB), we take -20*log(Vin*Gain/Vref). At Gain = 1, the time domain and FFT results seem to match well. For the first time-domain plot, -20*log(50 mVp / 2.4 V) = -33.62 dB. Note that this is equivalent to comparing the peak-to-peak voltage (100 mVpp) to the full-scale range (FSR = 2*VREF = 4.8 V): -20*log(100 mVpp / 4.8 V). 2. If the magnitude of the time-domain data looks incorrect, that's a different issue. Please confirm that the output of your function generator is giving the correct amplitude by probing the input pin of the ADS1298 channel. Remember that your Output Configuration setting in your signal source should be configured for High-Z termination, NOT 50-ohm! Can you clarify what supply configuration you are using and what voltage are you applying to the negative channel input pin? I'm still a bit perplexed about your other results: in the time domain, 200 mVpp should translate to -27.6 dB in the FFT (and 400 mVpp should translate to -21.5 dB). Best regards,
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