Lead Lag Filter

Thread Starter


Joined Mar 3, 2012

I started working on a project that involves applying a lead lag filter for the Loop filter of a CD4046 phased lock loop..

I'm still learning the 4046 and i was wondering if anyone could shed some insight on how to tune the lead lag filter loop to meet specific capture / lock on frequency range? Im having a hard time finding info on lead lag filters and how to apply in this manner

Mr. Turdnugget

panic mode

Joined Oct 10, 2011
lead lag filters are used as compensators for LTIs.
i'm not sure why would one need it for 4046. datasheet shows circuit and info needed to make functional PLL.

Thread Starter


Joined Mar 3, 2012
Some of the 4046 data sheets show lead lag filters.. but none of them show the math for applying them.. They all refer to a reference from a book written in the 60's.

So what would the lead lag filter be used to do?... with a 4046? if its shown on page 2 of this data sheet..


What are the applications?


Joined Mar 14, 2008
The lead-lag filter is used with a the Type I phase detector. If you use the Type II phase comparator, you just need a simple RC filter, and the lock range equals the frequency range of the VCO.

What is your application?