It also includes a passive low-pass filter to make the sound more pleasant to the ear, especially for younger players of the machine. He’s released the source code on his GitHub page for anyone ...

When I wrote a feature on automating oscilloscope readings, the example I used was the characterisation of a 7th-order 30 MHz low-pass filter.

A research team from Singapore has successfully designed the world's smallest on-chip low-pass filter which is 1,000 times smaller than existing off-chip filters.

For example, a programmable second-order, low-pass Butterworth filter with a corner frequency ranging from 200 Hz to 20 kHz can be designed by setting C1 = 0.022 µF and C2 = 0.1 µF.