Custom Search
Over 10000 Pages Indexed
Your Host
Click here to read about RF CafeKirt
Blattenberger

... single-
handedly
redefining
what an
engineering website
should be.

View the YouTube RF Cafe Intro Video Carpe Diem!
(Seize the Day!)

5CCG (5th MOB):
My USAF radar shop

Hobby & Fun

Airplanes and Rockets:
My personal hobby website

Equine Kingdom:
My daughter Sally's horse
riding business website -
lots of info

•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<

Job Board

About RF Cafe©

RF Cafe E-Mail

PLL's an more important Low pass folter - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


electrodummie
Post subject: PLL's an more important Low pass folter Posted: Thu Aug 09, 2007 2:27 am

Lieutenant


Joined: Wed Sep 15, 2004 3:15 am
Posts: 4
Location: Huntington beach
Well first i would like to know if anyone knows any online places that have goos info on pll's? searching i only came up woth some very basic stuff like wkipedia.
But my main question is on the after the phase comparator the lpf (can this be a band pass?) and how exactly does it effect settleing time. I would think a narrower bandiwidth will lock loop faster since it would pass less noise. And i thought that the filters job was just to pass dc because thats what input to the varactor on the vco?

Sorry for the "newb" question but i actually never seen a pll circuit, we use it internal to the chip so i cant probe around.


Top

nubbage
Post subject: Posted: Thu Aug 09, 2007 5:39 am

General


Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
Try www.circuitsage.com
That site provides design guides and design routines for Mathcad
Hope it helps.


Top

IR
Post subject: Posted: Thu Aug 09, 2007 10:36 am

Site Admin


Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
The only filter possible in PLL is a LPF. The purpose of the LPF is to smooth the output of the FPD (Frequency Phase Detector) and it sets the speed of the loop.

A wide filter will cause the loop to react faster, since the filter's pole(s) is/are located far, therefore, the filter has a wider reponse. The tradeoff, as you mentioned, will be a degradation in phase noise and vice versa.


Top

electrodummie
Post subject: Posted: Thu Aug 16, 2007 4:33 pm

Lieutenant


Joined: Wed Sep 15, 2004 3:15 am
Posts: 4
Location: Huntington beach
Thanks. i had not had the chance to thank you guys been doing alot of reading.
I do understand pll better but not enough yet.



Posted  11/12/2012
A Disruptive Web Presence

Custom Search
Over 10,000 pages indexed! (none duped or pirated)

Read About RF Cafe
Webmaster: Kirt Blattenberger
    KB3UON

RF Cafe Software

RF Cascade Workbook
RF Cascade Workbook is a very extensive system cascaded component Excel workbook that includes the standard Gain, NF, IP2, IP3, Psat calculations, input & output VSWR, noise BW, min/max tolerance, DC power cauculations, graphing of all RF parameters, and has a graphical block diagram tool. An extensive User's Guide is also included. - Only $35.
RF system analysis including
frequency conversion & filters

RF & EE Symbols Word
RF Stencils for Visio

Product & Service Directory
Personally Selected Manufacturers
RF Cafe T-Shirts & Mugs

RF Cafe Software

Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel