Electrical – Beaglebone PRU PWM to Audio Signal

analogaudiobeaglebone blackpwm

I was wondering if its possible to convert the high frequency PWM output from a Beaglebone Green's PRU into an analog audio signal. I was looking at building a low pass filter and I was wondering if that is the right direction to go?

Best Answer

To answer your question, yes, this is a common solution in pin/feature constrained designs. But as Mark pointed out, there are some peripherals available to you with the Beaglebone board that may be better suited to this. Depending on the way you implement it, you will need to somehow continuously update the PWM signal (most likely at 44.1Kz if you want "CD quality" audio, lower rates will still work for most sounds) on a clock or timer. what you need to do is design your low-pass or reconstruction filter to minimize the signal from feeding through to your audio signal. Consider this picture. enter image description here