[time-nuts] Re: 4096 PLL - how to switch off on-chip VCO

[glen english LIST]

Be aware of power supply noise rejection- or the lack of it.

The 4046 phase comparator etc - they all have VERY LOWÂ  almost zilch 
power supply noise rejection, IME.

Same with CMOS gate oscillators etc.

ADF4002 is a good chip. , Agreed Bob.

I'm assuming this design is on a multilayer PCB ?

On 23/02/2022 12:09 am, Bob kb8tq wrote:
> Hi
>
> Best guess:
>
> Your 10 MHz (for whatever reason) is being turned into a fast edge
> square wave. That’s dumping current spikes into the supply and ground
> on your board. You have a really wide spectrum as a result ( usually
> well up into the GHz region).
>
> That “stuff” is going here / going there. Some of it is getting into your
> amplifier / filter chain by one route or the other. It looks like modulation
> because of the filtering in your multiplier chain.