[sdiy] VSM201 Vocorder Question

[Tom Wiltshire]

+1 totally agree

If you can produce a 1% pulse width, you still only get -40dB. You need to get a 0.01% pulse wave to get -80dB. Tough to do. Not impossible, but awkward enough to make it stop seeming like such a great solution.

I've thought about this a bit because of using the PIC's PWM module so much. The best case output from that is either 8-bit or 10-bit, which means that -60dB is about as good as I'd get using it for a VCA, and that implies having a switching frequency which is much too low (31KHz) for many jobs.

Tom


On 2 Jan 2016, at 19:42, rburnett at richieburnett.co.uk wrote:

> <snip>
> Control range of PWM'd CMOS switches acting as VCAs isn't that great though.
> 
> -Richie,
>