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Waveform averaging - the PicoScope way

Forum for discussing PicoScope version 6 (non-automotive version)

Re: Waveform averaging - the PicoScope way

Postby lab!fyi » Fri Aug 11, 2017 12:36 pm

Noticed averaging keeps same "sample interval" as current sample rate dictates. But does not keep phase with original signal. When starting capture it assumes some random position within total "play" approx same as sample interval. Average trace is in magenta, and max play observed is marked with cursors. Sometimes, randomly, it starts in correct phase and keeps it.

PS6__bug__averaging__phase_shift__NOTOK.jpg
Average trace phase shifted


PS6__bug__averaging_phase_shift__OK.jpg
Average trace ok, lucky strike


Perhaps averaging should also have [option of] higher res horizontally, than current sampling rate, to work sort of like ETS works.

PS. Please increase allowed attachment size - 256KB not enough for screenshot PNGs and even JPGs, if do not compress to garbage!
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Re: Waveform averaging - the PicoScope way

Postby lab!fyi » Fri Aug 11, 2017 1:13 pm

When observing some other similar product noticed that sample points on normal trace are aligned with trigger pos. When enable averaging it also keeps same sample interval as regular trace, and also keeps sample points aligned with trigger pos. Getting more smooth trace is governed by "oversampling" control (2X, 4X, etc).
With this system averaged trace does not shift in phase.
Probably Picos "non aligned" triggering system is more accurate but need to account for it in secondary processing.
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Re: Waveform averaging - the PicoScope way

Postby Martyn » Fri Sep 01, 2017 8:13 am

Thank you for the comments which will be passed on to the development team for further discussion.

There are many data paths from the analog front end of the scope through to the display of data on the screen so, although a suggestion may seem easy to implement when looking at it in isolation, it may not be as straightforward in context of the full system.
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