[sdiy] CMOS CD4046 ring mod??

[matti]

On 29 Dec 2001, Tom May wrote:

> I think I was thinking of the 565 PLL, not the 4046.
>
> Phase comparator 2 in a 4046 is not a multiplier, it's a digital
> leading edge sensor thingy, there's a state diagram for it in the
> Motorola CMOS Logic databook (or the Fairchild doc at
> http://www.fairchildsemi.com/ds/CD/CD4046BC.pdf) which makes sense if
> you step through it.
>
> Tom.
*snip*

I have and use that circuit; it is indeed the 565. As I remember the
schematic correctly, (not that I really understood it), it seemd that the
input would modulate the oscillator on the 565; you couldn't use two
inputs to multiply each other. it can be a litle bothersome sometimes.
it's _very_ picky about the voltage it gets; too little (enough for most
other circuits), and it rings, but doesn't modulate. doesn't have the best
carrier rejection either. that said, it works nicely.

enjoy


-
the chatter has stopped. oh joy. achmed, yon achmed, make my felt.