# Aliasing: Why Your Oscilloscope May Be Lying To You [E223]

Page: https://stenobird.com/podcast/diagnosing-the-aftermarket-a-to-z-4411651/aliasing-why-your-oscilloscope-may-be-lying-to-you-e223
Text version: https://stenobird.com/podcast/diagnosing-the-aftermarket-a-to-z-4411651/aliasing-why-your-oscilloscope-may-be-lying-to-you-e223.md
Podcast: [Diagnosing the Aftermarket A to Z](https://stenobird.com/podcast/diagnosing-the-aftermarket-a-to-z-4411651)
Published: 2026-02-11T04:15:00+00:00
Episode link: https://automotiverepairpodcastnetwork.com/aliasing-why-your-oscilloscope-may-be-lying-to-you-e223
Audio file: https://episodes.captivate.fm/episode/6bbdf48e-8f6d-4ed2-ae30-f7eb85e56687.mp3
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JSON: https://stenobird.com/v1/public/podcasts/diagnosing-the-aftermarket-a-to-z-4411651/episodes/aliasing-why-your-oscilloscope-may-be-lying-to-you-e223
Duration seconds: 2012

## Resource

Thanks to our Partners, Pico Technology and Autel Watch Full Video Episode Matt answers listener emails about oscilloscope aliasing—what it is, whether all scopes can do it, and how it can trick you into diagnosing failures that aren’t real. Using a “pegboard and golf tees” mental model, he explains how a digital storage oscilloscope samples voltage, stores it in memory, and then reconstructs what you see on-screen. The key takeaway: aliasing isn’t magic, it’s math—specifically the relationship between sample rate, timebase, and memory buffer. He also explains why some scopes (especially Snap-on) behave differently than Pico-style workflows, and how misunderstanding that screen-to-buffer relationship can create fake-looking “dropouts.” Who This Episode Is For Anyone using a handheld/PC-based automotive DSO (Pico, Snap-on, Autel, etc.) Techs chasing intermittent cutouts, crank/cam dropouts, injector events, CAN glitches Anyone who has ever said: “The waveform looked wrong… but the fix didn’t fix it.” Key Topics Covered What aliasing is (in plain language): the scope fails to accurately reconstruct the waveform you’re testing. Can all oscilloscopes alias? The spicy answer is yes, they all can—especially digital scopes—depending on setup and limitations. Analog vs. digital (audio analogy): Digital sampling is like digital audio—there are “samples,” and reconstruction depends on how well you capture the real signal. The “pegboard model” for DSO operation: Up/down holes = voltage levels (vertical resolution). Left/right holes = time positions (sample points in memory). The scope measures voltage, then “plants a peg” in memory and connects the dots. Vertical resolution vs. time performance: 8-bit can look stair-steppy. 12/16-bit improves vertical accuracy. But most real-worl…

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## Transcript

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