Search found 3 matches

by abelian
Mon Feb 19, 2018 3:31 am
Forum: Octo Sound Card for the Pi
Topic: Artifacts when capturing at 96k/sec
Replies: 0
Views: 999

Artifacts when capturing at 96k/sec

Glitches occur as the input signal moves through about +1.3V and -1.3V, as highlighted in the following capture of a 130Hz 5.0 Vpp sine wave: http://abelian.org/vlf/tmp/180218b.gif This is channel 1 on the Octo, at 96k/sec with input gain set at the default 38 in alsamixer. The glitches always occur...
by abelian
Thu Jan 25, 2018 8:54 pm
Forum: Octo Sound Card for the Pi
Topic: I2S sync errors
Replies: 3
Views: 1337

Re: I2S sync errors

Thanks Matt, Yes the root cause was with my application! The I2S sync error messages appear to be a normal result of starting or restarting the ALSA read interface. Hence I get a sync error in dmesg every time the application gets a read error and calls snd_pcm_prepare(). The read errors turned out ...
by abelian
Wed Jan 24, 2018 6:25 pm
Forum: Octo Sound Card for the Pi
Topic: I2S sync errors
Replies: 3
Views: 1337

I2S sync errors

Running capture at 96k frames per second, I get frequent but irregular soundcard read errors, with errno saying 'Broken pipe'. Operation is restored by calling snd_pcm_prepare() again on the device. Happens up to four times per hour, sometimes it will run for a couple of hours between occurances. Ea...