Currently I am working on a project with a stm32f302c8t6 mcu which I monitor an analog signal. I generate a tone using dac when the signal exceeds a certain treshold. My problem is that as soon as I generate the audio the analog signal path is interferred by the audio signal. The audio is output with a buzzer. At first I thought that the current drawn by the buzzer might be the reason.
The dac output is a 440 Hz sinewave. I tried a seperate power supply with a dedicated 3.3v regulator for the audio section with a combination of several bypass capacitors with no success. Any recommendation will be highly appreciated.