Osc reset time

[Fraser, Colin J]

> -----Original Message-----
> From: Haible Juergen [mailto:Juergen.Haible at nbgm.siemens.de]
> Sent: 16 December 1998 15:41
> To: DIY; Fraser, Colin J
> Subject: AW: Osc reset time
> 
> 	>If you have a dual two-way analogue switch, with very low on
> resistance, you
> 	>could connect the capacitor so that you can reverse 
> its polarity in
> the
> 	>circuit - ie a comparator detects the peak level and 
> toggles the
> switches so
> 	>that the connections from the cap to the ref voltage and the
> current source
> 	>are swapped.
> 
> And now, connect two high impedance buffers and a differential
> amplifier directly to the capacitor, and you have a triangle wave
> without extra conversion as well.

The triangle wave would be an octave lower than the saw - but that might be
a plus.
You could have a triangle 'sub' osc output, and a tri convertor (with
variable DC offset ;-) for the normal tri output, or just rectify the sub
octave tri-wave.
The control signal for the cap swapping switch would also be a sub octave
square wave for free.

I'll have a look for a suitable analogue switch over the weekend and
prototype this idea.

> I haven't checked for disadvantages yet, but it looks very promising !

Hopefully you wont find any show-stoppers :-)
One question is how to implement the extra cap for precise linear detune.


Colin f