@mdp I2S signal? That's a very jittery clock.
@mansr yes and yes
@mdp What is it?
@mansr A64 w/ WM8731. DAC input on the bottom.
@mdp How does it sound? That amount of jitter ought to cause easily audible distortion.
@mansr qualitatively it sounds fine, I was surprised. I will get some oxygen free cables and retest. 😉
@mdp Fine is such a vague term. If you play a 10 kHz tone, you should be able to hear the difference compared to a clean device. Exactly what it sounds like obviously depends on the jitter spectrum.
@mansr yup, pretty early in my investigation. I have some more serious issues with noise on the mic first. of course, also hampered by the mainline mv64xxx i2c controller sometimes stalling. much fun.
@mdp looks fun! I haven't had the chance to prototype anything at work in while (though I've been doing it a lot at home.) For a lot of things it's becoming increasingly impractical. By time the HW group gets me schematics and they pass my review we usually end up able to spin boards that are at least 95% of the way there. Sometimes jumper wires are required or we find minor problems that get changed on the next board rev. I still miss hooking all it up and seeing it work first.
@mansr for $6 with immediate shipping? Could even get it next day if I needed. It's not a cost issue, it's a feedback time issue. In @mdp 's case the prototype hardware is blocked so it's quickest way to proceed. It's often possible to find existing boards with the bits you need to do your initial testing anyway. Believe it or not there are still people that etch their own boards just so they can turn a prototype in a few hours.
@georgem @mansr indeed it's often difficult to find the exact bits you need on a board, right number of xyz interface exposed, much less the right peripherals attached to them. and also, working Linux support for those peripherals. There's a lot of stuff claimed to be working...until you get into the details and find all the corners that have been cut in drivers.
@georgem I had to do an entire 3-4 month calendar time project having never received the custom hardware (until a few days go). all my audio processing work done on rpi3, one onsite trip to test some stuff on their board and my colleague testing my stuff on his custom hardware. Still waiting on the hardware/bsp supplier to deliver working ALSA drivers, the stuff they sent has periodic impulse noise that totally breaks AEC algorithms. nmfp :)
@georgem fwiw, all I'm doing here is trying to do a "quick test" of our audio pipeline on some different hardware from the broken custom stuff. not going so quickly atm.
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