[sdiy] VCO reset time

[Czech Martin]

> This seems a more likely reason for using that topology. Plus the 
> charging current itself never changes, but is steered around to 
> different integrators.

Yes. It is often forgotten that bipolar transistor current
sources only work as such under steady consitions.
All abrupt changes will of course introduce some error
for some time.

This is the reason that very fast circuits use a current source
and at least two switches, with correct biasing the current
source will see no voltage glitch, hence the current remains
stable all the time.

Something that is not at all happening in a simple saw core.

m.c.