EEVblog #442 – Analog Vs Digital Oscilloscope Noise

Is a modern digital oscilloscope noisier than an old analog CRT oscilloscope?
Are analog scopes better at displaying signals?
You might be surprised.when Dave demonstrates the display of some common mode noise on both types of oscilloscope.
An aside video from the common mode noise video

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    • Mario

      Well, that title is quite deceiving….
      It should be “who displays noise better”…

      Your title suggests that you investigate into the noise of the analog frontend…

    • So if the noise is coming from the power line I bet you can calculate the frequency. For example, I note on the digital scope the spikes seem to be at a regular period.

    • Russell Shaw

      My 30yr old BWD cro is *way* better than that DSO garbage for displaying noise.

      And i don’t mean crap picked up from SMPSs.

      Noisiness on the trace with the input shorted at the front panel.

    • Worf

      Dave, you mentioned in the video that the reason you see the noise better on a digital was because of its slower update rate. Given you have a “slow” Rigol, a faster Agilent 2000 and the million-upaates-per-second Agilent 3000, could you do a comparison?

      After all, that would imply the 3000 series scope you could miss the noise as well?

      • Yes, the more “analog like” a digital scope gets, the closer you get to having the same effect. Only, the digital scope can have infinite persistence.

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