Resources regarding Phase Locked Loops?

Has never been mentioned? Ouch. What university was that?

If you've never done a PLL I suggest to get a copy of the ARRL Handbook. Mine are older but PLL is handled in there. If this is for a mass product and it's on a tight schedule get consulting help.

I think Analog Devices has some good app notes about the topic as well. So did Philips but then they messed up their web site.

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Regards, Joerg

http://www.analogconsultants.com

Phase-Locked Loops, 5th Edition Roland E. Best McGraw-Hill, June 2003, ISBN 0071412018

Cheers!!

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Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in the 
address)

Life is like a roll of toilet paper; the closer to the end, the faster it goes.

It's not that PLLs aren't covered at all - they're covered in some classes, just none that I have taken. I took a pretty specialized courseload, and PLLs are far from my specialty. However, it looks as if I'm going to have to learn the buggers.

It's not for a mass product (at least not on a strict timeline - eventually I hope to bring this device to market)

I'll take a look at the ARRL handbook. I see it mentioned enough that I should check it out anyways.

-Michael

martin

That's the old 4046 style stuff. I thought Michael meant some "real" PLL apps. Philips used to have nice app notes about that as well. Maybe they still are somewhere on their server. It's just that it has been becoming so fluff-laden and freaking slow. I understand that it's faster from Europe but that doesn't help us much here in the Wild West.

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Regards, Joerg

http://www.analogconsultants.com

I know its old, but the 7046 goes upto 20ish megs, and the basics are covered in the data sheet. But Micheal didn't really say how little he knows

I had a quick browse on th nxp site for the app notes, it seems you have to email them for a copy, pathetic.

I'll try to find a rather good (IMHO) philips PLL appnote on my backup drives/CD, and stuffit somewhare accesable

martin

IIRC it's more like 17-ish. And probably only under the full "Princess on a Pea" treatment, and when Mars is in the correct constellation and no black cat has crossed the road from left to right.

IMHO that whole web site has become pathetic, almost to the point of being useless. And then some day they'll wonder why the sales numbers don't come in as expected.

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Regards, Joerg

http://www.analogconsultants.com

4046 or its superfast 74HC4046 or 77046 sisters are a good start for a begining PLL person, but are junk compared to whats out there now. However for about 3$ in parts plus a power supply and voltmeter or perferably a oscilloscope, it will get you started learning and may actually solve your problem, although a difference counter seems much more like a solution for you

if you want to start with the 4046 as a learning experience, harry Lythall's pages are great:

or the tutorials here:

click on "projects" then click on "synths"

Steve Roberts

I always found the Lagrange Point pretty good for PLLs

martin

Isn't that where a big enemy spacecraft was hiding in Star Trek?

Anyhow, I prefer the liquid versions:

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Regards, Joerg

http://www.analogconsultants.com

My God. My community college engineering TECHNOLOGY students get a full week of PLL in the second semester of their FRESHMAN year. I'd like to know, just to avoid, what university are we talking about?

Jim

I have never, ever done anything with PLLs. My

You have got to be kidding me. Why post such nonsense? Is this some sort of way to fluff yourself up? An attempt to put others down? Perhaps a way of compensating for an insecurity about a shoddy education, or a lack thereof? It's pitiful, sad, and a failure on all counts.

To answer your question - I attend the 3rd ranked university for EE in the USA.

I would suggest that your CC is teaching it too early, as there is no way in hell that they have a strong enough background to understand how it works at that point. Just having quickly glanced at the math behind PLLs I can say that. Learning implementation should follow understanding, in my opinion. I suspect those running your CC feel differently.

-Michael

Not a lot of ever EE's get to design PLLs. That should certainly make an elective of the material. ETs often have to troubleshoot PLLs is existing equipment, that is the difference engineers and technologists. To clarify it is the difference between having to have the background to analyse it for design, and having to have a basic understanding of typical industrial applications and their various uses. Or quickly, between designing the chip and using the chip.

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 JosephKK
 Gegen dummheit kampfen die Gotter Selbst, vergebens.  
  --Schiller

Not sure what you're trying to accomplish, but I'd be inclined to use a mixer, followed by a baseband filter, digitizing and appropriate signal processing. An Analog Devices AD734 linear multiplier would make a nice mixer.

If the two signals are locked (in a PLL ...) then mixing would be a fairly pointless exercise. The O/P is after phase difference.

In a filtered DC mixer (multiplier) output the phase difference shows up as a varying DC voltage which can be analyzed for phase jitter and slower variations with time. I don't see the role of a PLL, per se. PLLs are used to phase-lock an output oscillator to an input signal. How does a second signal fit in, two PLLs? Or are you only thinking of the PLL's phase detector? Remember, this is after all just a mixer! But often, like in a 4046, it's not a very good one, not as good as an accurate linear multiplier.

Since the OP wants to find the phase difference of two input signals (one clean, one noisy) maybe two PLLs wouldn't be such a bad idea. He could then trivially mux the two oscillator outputs, both of which would be clean, of equal amplitude and 50% duty cycle.

But as I've never done this I may be way off track here.

robert

Cleaning a signal with a PLL is just getting the signal through a narrow BPF (and adding some noise and phase error too). Mixing two PLL'ed signals the translates your BPF center frequency to zero, transforming it to an LPF.

Multiplying the signal first and LPFing it after is just the reversing the operations (first translate your frequency, then LPF it).

They are both mathematically equivalent, but I'd try to avoid the PLL noise. If the frequency is low enough I'd go for the multiplier first and LPF later, and otherwise probably for a DBM and LPF.

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Thanks,
Fred.

Yeah, sounds right. Like I said, I'm out of my depth here.

robert