3 ms·
Wouldn't you typically want to run that output through an RC (low pass resistor-capacitor) filter to average out the voltage and eliminate high frequency PWM no
by robmccoll 3y ago
Wouldn't you typically want to run that output through an RC (low pass resistor-capacitor) filter to average out the voltage and eliminate high frequency PWM noise? Is that built into the pico?
- praash 3y agoThis would be required for a true DAC, but not here: - A physical speaker already acts as a filter due to inertia - The PWM frequency and its square harmonics sit far beyond the human hearing range
- crote 3y agoYou'd normally do that, yes, but it's not strictly required in all applications. The speaker itself might already act as a low-pass filter simply because it can't physically react fast enough for the high-frequency part.
- duped 3y agoWell then you wouldn't be playing audio without a DAC, would you?
- jalk 3y agoHow would you consider an RC filter a DAC? there is nothing digital about it
- duped 3y agoIt's a reconstruction filter, the simplest DAC you could build. Most of the digital parts of DAC chips are not there for conversion, but getting data ready for conversion through a reconstruction filter. You don't need that if you're driving a PWM signal through a cap to integrate it.