VCO

[BJ]

Grant Richter wrote:

> Could you elaborate on that? I don't have the schematics for the OSCar. How
> does it use a phase locked loop?
> 

Well,well pom di pom,if you and other people want to know how OSCar
osc's are used,
i can send a JPG scaan of the oscillator section.But remember this is
a hand drawn shematic.....around 58k large file containing one OSC.

> important unless you intend to use the PLL's output control voltage to
> drive highly linear VCOs.  If the 74HC7046 or 74HC9046 are quite a bit
> more linear, then I will want to try this.  Especially since I've
> already been able to eek out more waveforms than just square.  Would
> anyone have the linearity spec on these parts?
> Scott

The 74HC7046 looks the same as 74HC4046 but lower power and a slightely
different PC3.
The 74HC9046 is a higer performance then 4046,they have(Philips)skipped
PC3 for a better PC2 that have a current source output stage, a band gap
for all internal references,higer impedance for the loop filter that
more or less acts as active PLL filter.And they claim lot more
better performance of the 9046.

Perhapps this one would solve your loop filter jumps!
For those who just want a plain simple linear high freq VCO there are
lots of better solutions then the 4046 VCO....a AD654 for example
or a plain simple LM13600 as VCO.
 
BJ in smorgas......