Bela analog out stepping?

luca_mucci

Hey guys,
has anybody experienced any stepping artefacts on the Bela analog out?
Very silly patch: generating some slow sinusoids in Pure Data (between 0.05 and 0.2Hz) and sending them out separately on the first four analog outs to generate CV signals to control some synth's parameters.
The stepping artefact is very audible: I went to a friend's who's got a professional scope and could see the stepping. It looked like the bit depth was ridiculously low, like literally 8 steps or something like that (unfortunately I couldn't take any picture nor videos, so sorry...)
I was wondering: maybe there's some flags or settings which might affect the bit depth of the analog outs?
As far as I can see from the documentation, there's not, but still thought was worth asking.
Thanks a lot for your help!
L

giuliomoro

That's completely unexpected, you should get about 65536 steps. Can you send your Pd patch?

luca_mucci

very trivial stuff tbh :

#N canvas 361 35 467 329 10;
#X obj 173 32 osc~ 0.5;
#X obj 48 131 +~ 1;
#X obj 47 159 /~ 2, f 5;
#X obj 40 32 osc~ 0.2;
#X obj 328 136 dac~ 1 2;
#X obj 93 204 dac~ 3 4 5 6;
#X obj 206 133 +~ 1;
#X obj 205 161 /~ 2, f 5;
#X obj 207 102 *~ -1;
#X obj 142 130 +~ 1;
#X obj 141 158 /~ 2, f 5;
#X obj 105 32 osc~ 0.05;
#X obj 97 129 +~ 1;
#X obj 96 157 /~ 2, f 5;
#X obj 328 35 adc~ 1;
#X connect 0 0 9 0;
#X connect 1 0 2 0;
#X connect 2 0 5 0;
#X connect 3 0 1 0;
#X connect 3 0 8 0;
#X connect 6 0 7 0;
#X connect 7 0 5 3;
#X connect 8 0 6 0;
#X connect 9 0 10 0;
#X connect 10 0 5 2;
#X connect 11 0 12 0;
#X connect 12 0 13 0;
#X connect 13 0 5 1;
#X connect 14 0 4 0;
#X connect 14 0 4 1;

giuliomoro

can you try to:

connect the analog outputs to the analog inputs
run this patch?

#N canvas 0 0 1280 774 10;
#X obj 173 32 osc~ 0.5;
#X obj 48 131 +~ 1;
#X obj 47 159 /~ 2, f 5;
#X obj 40 32 osc~ 0.2;
#X obj 328 136 dac~ 1 2;
#X obj 93 204 dac~ 3 4 5 6;
#X obj 206 133 +~ 1;
#X obj 205 161 /~ 2, f 5;
#X obj 207 102 *~ -1;
#X obj 142 130 +~ 1;
#X obj 141 158 /~ 2, f 5;
#X obj 105 32 osc~ 0.05;
#X obj 97 129 +~ 1;
#X obj 96 157 /~ 2, f 5;
#X obj 328 35 adc~ 1;
#X obj 445 278 adc~ 3 4 5 6;
#X obj 435 337 dac~ 27 28 29 30;
#X connect 0 0 9 0;
#X connect 1 0 2 0;
#X connect 2 0 5 0;
#X connect 3 0 1 0;
#X connect 3 0 8 0;
#X connect 6 0 7 0;
#X connect 7 0 5 3;
#X connect 8 0 6 0;
#X connect 9 0 10 0;
#X connect 10 0 5 2;
#X connect 11 0 12 0;
#X connect 12 0 13 0;
#X connect 13 0 5 1;
#X connect 14 0 4 0;
#X connect 14 0 4 1;
#X connect 15 0 16 0;
#X connect 15 1 16 1;
#X connect 15 2 16 2;
#X connect 15 3 16 3;

- open the scope window, zoom out, what do you see ?
I get something like this :
alt text