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EspoTek / Labrador

EspoTek Labrador is a USB device that transforms your PC or smartphone into a fully-featured electronics lab. This repo holds all of the source code!
http://espotek.com
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Oscilloscope range clipping #232

Open MrDerples opened 1 year ago

MrDerples commented 1 year ago

The oscilloscope display will clip voltages past a certain level until channel 1 is paused and unpaused. The negative range seems to be clipped at -1.37 V and/or -4.65 V, while the positive channel seems to clip at +4.65 V. I've observed this behavior on both channels under a number of different operating conditions, and the steps below seem to be the bare minimum needed to replicate it:

1) Open the Labrador software. Connect a signal source between oscilloscope channel 1 (DC) and ground, and feed it a signal that will exceed -1.37 V and/or +4.65 V. For purposes of illustration, I used a 1 kHz, 10 Vpp sine wave centered on zero, but the nature of the signal, or whether or not the Labrador's signal generator is being used to provide it, doesn't seem to matter. I also set the trigger level to zero, but you can observe this with an untriggered acquisition, too. Note the channel 1 max and min values.

clipping_1

2) Change the vertical range to something that should show the whole waveform. In my example, -6 V to +6 V. You will observe that the waveform is clipped at the levels previously mentioned, like in the image below.

clipping_2

3) Pause acquisition (click the "Paused" checkbox"), then un-pause it - the waveform will no longer be clipped.

clipping_3

For reference, I'm running on Windows 10 Enterprise 21H2, build 19044.2311. The Labrador software is git hash 2cc0678, downloaded from Github on 2022-12-02 (New York time). I've been able to replicate this on multiple Labrador boards.

EspoTek commented 1 year ago

Very clear report. I know exactly what would cause this and will get it fixed up after Christmas.