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ADS1298: squarewave input to converter: output digitized signal has round edges

KLaus K.
Prodigy 50 points
Part Number: ADS1298

Tool/software:

Hi

on ADS1298 I configured 250 Hz. I configured my signal generator to square wave of 20ms duration.

I stream my data to PC and plot it there. What I oberserve is that get 2-3 Values in between the high and low voltage of my signal.

Why are the edges not super sharp? Why are there the 2-3 intermediate values between high and low voltage?

  • 0
    TI__Guru 66466 points

    Hi Klaus,

    Thank you for your post.

    Two things could be limiting the slew rate of the converted waveforms:

    1. R-C time constants may be filtering out the high-frequency content of the analog square wave, thus rounding the rising/falling edges. 
    2. Undersampling of the input signal may lead to missing detail in the output waveform. Can you clarify the input signal frequency? You mentioned sampling at 250SPS.

    Regards,

    Ryan