Strange waveform with no inputs!

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mazzerman
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Joined: Sun Jul 05, 2020 9:42 am

Strange waveform with no inputs!

Post by mazzerman »

I have recently purchased a 2204a and wanted to try get a can bus waveform.
I plugged in the Pico and it was recognised in Pico 6 but before I put any probes in the unit I got a peaking waveform (iv tried to attache a photo showing the waveform with no inputs. But I just get "file to large" no matter how much I crop it)
I would have expected to see only a flatline. Have I got an issue with my new unit?

Gerry
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Joined: Mon Aug 11, 2014 11:14 am

Re: Strange waveform with no inputs!

Post by Gerry »

Hi mazzerman,

No, that is to be expected.

What you are seeing is the noise being picked up on the input with nothing attached. The PicoScope has different input ranges (so that you can set the best amplification for the signal, in order to give you the largest waveform on the display without clipping). If you have your probes attached to something generating a signal when you connect it, or when you start the software with the PicoScope already connected, the software will automatically switch to the best input range for the signal. As you have no probes attached, the input signal is just very low level noise, so the software switches to the lowest input range in order to give you the best view of it. if you connect your probes to a valid signal source with a decent signal level the noise will only be visible as a tiny ripple,

Regards,

Gerry
Gerry
Technical Specialist

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