| Electronics > Beginners |
| Why is my oscilloscope showing a signal? |
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| StillTrying:
With only 2.5 samples per division and in dots mode, and going by its large amplitude for that high a frequency, is that 84MHz real or could it just be an aliasing effect. :-\ ...I'm going for aliasing. :popcorn: |
| hermitengineer:
--- Quote from: StillTrying on November 17, 2019, 09:16:47 pm ---With only 2.5 samples per division and in dots mode, and going by its large amplitude for that high a frequency, is that 84MHz real or could it just be an aliasing effect. :-\ ...I'm going for aliasing. :popcorn: --- End quote --- It may even be half that. Isn't the 500Ms/s divided between the two channels? If so, each trace gets 1.25 samples per division. Or does the scope sample one trace on each pass and alternate between them? I remember old analog scopes that did that. |
| tautech:
Change Trigger Holdoff to Close (minimum). (press the button) Remove Ch2 probe, is the signal still there ? If yes, then one by one turn OFF ever other thing within some meters proximity. Wallwarts and anything running SMPS are notorious for EMI. Careful elimination will find the culprit. |
| StillTrying:
What's the 84.11MHz 5Vpp signal like on 500 and 250ns/div. |
| hamster_nz:
Last time I had something like this it was a "Baby Monitor" on the other side of the wall, in the room next door. |
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