[sdiy] A question about Chorus

[Richard Wentk]

'Quantisation' was the wrong word to use there. 

What I meant was that sampling always includes a measurement error, because you can never measure an instantaneous value perfectly accurately, no matter how you do it - although you can get away with a good average across a single sample period, if you can contrive that, and your clock is jitter-free. (Neither applies in an analog BBD.)

Digital sampling adds a further error by snapping the measurements to a grid. But analog sampling still includes other errors.

There's also a basic limit to precision which is set by the noise floor, defined by various physical limits including thermal noise, shot noise, BBD slop, and others.

So taken together, analog sampling is a long way short of what's needed for perfect Nyquist/Shannon sampling.

Richard

> On 1 Sep 2013, at 00:22, Mattias Rickardsson <mr at analogue.org> wrote:
> 
>> On 1 September 2013 01:08,  <rsdio at sounds.wa.com> wrote:
>> A capacitor can hold any possible voltage (within its maximum limit), only
>> quantized at the Coulomb level when you consider discrete electrons.
> 
> This is interesting.
> 
>> However, any analog circuit is quantized at the discrete electron level, so
>> a BBD is no more quantized than a single-pole low-pass filter.
> 
> Except for differences in signal level above the discrete levels
> (resolution, in terms of that quantisation).
> 
> How small are these discrete steps in the signals of actual circuits?
> Are there any circumstances when they may become relevant in audio
> electronics at all?
> 
> /mr