[time-nuts] Digital PLL ICs, alternatives and digital loop filters

John Miles jmiles at pop.net
Sat Dec 16 20:01:45 EST 2006


Yeah, for one OCXO disciplining another, I'd just use a 74F90 and 74HCT4046, 
like that quick-and-dirty design did.  The loop gain will be low and the 
integration period will be measured in seconds or even minutes, so I don't 
believe noise is going to be worth worrying about.  It would be hard to 
screw up too badly in this scenario.

As far as modern chips go, the ADF4002 is a new favorite of mine.  It's 
capable of very high performance at N and R ratios down to 1... but it will 
require a microcontroller.   You also need to be comfortable doing your own 
loop design for it.  (I am suspicious that ADIsimPLL has a bug that gives 
misleading results with small KVco values, but am not entirely sure about 
that yet.)

-- john, KE5FX

----- Original Message ----- 
From: "Didier Juges" <didier at cox.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Saturday, December 16, 2006 2:50 PM
Subject: Re: [time-nuts] Digital PLL ICs,alternatives and digital loop 
filters


> John Miles described a clean 110 MHz PLL from a 5.5 MHz source, which he
> used in his tracking generator project.
> http://www.thegleam.com/ke5fx/tr503.html
> 




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