[sdiy] PWM to voltage (was Re: wireless patching)

[Tom Wiltshire]

On 27 May 2017, at 01:08, Quincas Moreira <quincas at gmail.com> wrote:

> That's right, converting PWM to voltage requires filtering, so there'll always be a bit of glide. 

This is true, but you can make it pretty minimal, depending on the situation.

I designed a PWM-based pitch transposer, which uses two PWM channels,  one to provide octaves, and the other to provide semitones. Since one channel only needs ten steps, and the other only needs 12, the PWM frequency can be very high (250KHz) and the required filtering can therefore be both effective and fast.

The project  finished up as this:

http://www.frequencycentral.co.uk/?page_id=1311

It's a pity that the technique wouldn't work for a full MIDI-CV convertor, but that'd need more resolution to get between notes, and then the benefit of only a few steps is gone.

Tom