Digital waves are not stair steps

April 16th, 2014 § 2 comments

I’ve always understood that a digital representation of an analog wave form looks like this:

Stair step wave formBecause you know, ones and zeros and all that. Well it turns out that the stair step wave form is simply an incorrect representation of a sample. We should actually be using a lollipop graph because there are no values between the points.
Lollipop
Most importantly if you convert that sample back to analog you get the original smooth wave form. I learned this and so much more in a nerdtastic video all about analog to digital conversion the noise it generates and how to use dithering to reduce it. I probably only understood half of what he said and did not expect to finish the full video but I got enough to keep me engaged through the end. You should at least watch the first 8 minutes.


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§ 2 Responses to Digital waves are not stair steps"

  • I actually have the HP signal generator (even older model than his old model) and the Tektronix oscilloscope. No spectrum analyzer though :’(
    Nice video. I got a lot out of pretty much everything except the dithering part. He lost me on that one.

    • Thomas Paine says:

      Yeah the dithering was pretty “in the weeds” but I still found it interesting. I just had to take his word for it at that point though.

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