What are these errors called? Oscilloscope traces shown

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jonathanjo
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What are these errors called? Oscilloscope traces shown

Post by jonathanjo »

Friends --

I'm having trouble with some output of an Audient id44 with Ubuntu Studio 18.04.

My *first* problem is: what are these errors called? Once I know how to describe these, then I'll ask about my detailed question. At this point I have no idea if these are an ordinary symptom of a configuration error or if they are indicative of some kind of driver bug.

The output is 440 Hz sine

Error type 1: "missing samples"
chopout_20200717_153540.png
chopout_20200717_153540.png (195.15 KiB) Viewed 738 times
Error type 2: "inserted pause"
silent_20200717_145151.png
silent_20200717_145151.png (186.16 KiB) Viewed 738 times


Thanks for any tips.

Jonathan.
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Re: What are these errors called? Oscilloscope traces shown

Post by raboof »

jonathanjo wrote: Mon Jul 20, 2020 2:12 pm My *first* problem is: what are these errors called?
I'm not sure if there's a single term for those errors. It is possible they are the result of 'xruns', which is the umbrella term for buffer underruns and overruns: the application generating the sine either producing too much data for the sound card buffer to keep up, or not producing enough data in time. Usually you would also find them in the logging somewhere.

What application are you using the generate the sine? How are you feeding it into your sound card?
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Re: What are these errors called? Oscilloscope traces shown

Post by folderol »

Apart from discontinuity, both traces are showing a DC offset towards the positive (unless the scope is out of callibration).
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Re: What are these errors called? Oscilloscope traces shown

Post by jonathanjo »

Thanks answerers!

raboof -- thanks, they do seem consistent with underruns and overruns. I'll ask proper question with all the environment and details later (this was `aplay`, with a cd-quality test tone.)

folderol -- "discontinuity" sounds a little mathematical, I'm not sure anybody would know what I meant if I said I was getting discontinuities in my output. I noticed the DC bias too, but that's not today's problem for me.
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