Re: PLL with external feedback at 622.08
bo...@mailinator.com
> Hi All
> I’m going to design a PLL for the frequency of 622.08MHz. This PLL
> should support external feedback. I’ve looked for such PLL muck but I
> haven’t found .
> What shall I do if such a PLL doesn’t exist?
> I know that there is many “phase and freq. detector” and VCXO from
> different vendors but I don’t know how to design Loop filter and
> charge pump.
> Is there any IC that integrates phase-frequency detector, loop filter
> and charge pump?
> I’ll very appreciate anyone who helps me.
I think you need to give more details of exactly what you
want to do. You want a 622MHz output, do you want to
lock to a 622MHz input or are you going to use a lower
reference frequency and a divider?
What do you mean by "external feedback"?
Bob
Vladimir Vassilevsky
sung...@gmail.com wrote:
> Hi All
> I’m going to design a PLL for the frequency of 622.08MHz. This PLL
> should support external feedback.
What this PLL supposed to do, exactly?
> I’ve looked for such PLL muck but I
> haven’t found .
There is plenty of PLL ICs from all major vendors.
> What shall I do if such a PLL doesn’t exist?
Buy a bottle of whiskey?
> I know that there is many “phase and freq. detector” and VCXO from
> different vendors but I don’t know how to design Loop filter and
> charge pump.
Read the appnotes.
> Is there any IC that integrates phase-frequency detector, loop filter
> and charge pump?
Check the PLLatimum series from National.
> I’ll very appreciate anyone who helps me.
How much is the "very appreciation" ?
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
o...@uakron.edu
telecomm project:
http://cgi.ebay.com/Vectron-Int-VCO-600A-Voltage-Controlled-SAW-Oscillator_W0QQitemZ350031564
622 dot something VCXO.
Steve Roberts
o...@uakron.edu
350031564988
Steve
Joel Koltner
news:47r8l.212$PE4...@nlpi061.nbdc.sbc.com...
Wait, I thought that was what you were supposed to do once you found a PLL
that *could* conceivably work, and had to start making it do so rather than
being able to tell your boss it really was impossible?!
> Read the appnotes.
...or Best's book, "Phase-Locked Loops" is a good
beginning-/intermediate-level text.
>> Is there any IC that integrates phase-frequency detector, loop filter
>> and charge pump?
> Check the PLLatimum series from National.
...or the ubiquitous ADF43xx series from Analog Devices.
---Joel
bo...@mailinator.com
> My bet is the OPs employer is trying to clone one of these for a
> telecomm project:
>
>
> Steve Roberts
My guess is that it is either clock generation or clock recovery
for SONET/SDH STM4 or wide area gigabit ethernet.
Telephone company stuff generally syncronises everything
to a master clock from a central office. Ocasionally
you hear storys of some little telecomms company that
used a link from a competitor as the clock source
for their entire network, until one day...
A VCO module such as the one on ebay that you mentioned
could form a part of a PLL to recreate a clock from
another souce.
Bob
That would just form part
Vladimir Vassilevsky
bo...@mailinator.com wrote:
> On Jan 5, 5:40 pm, o...@uakron.edu wrote:
>
>>My bet is the OPs employer is trying to clone one of these for a
>>telecomm project:
>>
>>622 dot something VCXO.
>>
>>Steve Roberts
>
>
> My guess is that it is either clock generation or clock recovery
> for SONET/SDH STM4 or wide area gigabit ethernet.
Ah, the low jitter and the high accuracy clock with multiple fallback
modes is completely different story. The amateur approach is not feasible.
BobW
"Vladimir Vassilevsky" <antispa...@hotmail.com> wrote in message
news:47r8l.212$PE4...@nlpi061.nbdc.sbc.com...
sung...@gmail.com wrote:
Read the appnotes.
Vladimir Vassilevsky
-------
622.08MHz means he's dealing with SONET. The SONET jitter specifications are
extremely tight.
The OP is WAY out of his league if he's asking questions like this and he's
doing a SONET project.
Bob
--
== All google group posts are automatically deleted due to spam ==
bo...@mailinator.com
> 622.08MHz means he's dealing with SONET. The SONET jitter specifications are
> extremely tight.
>
> The OP is WAY out of his league if he's asking questions like this and he's
> doing a SONET project.
>
> Bob
The original message appears to have come from
Iran College of Tele-communications in Tehran
so the OP is most likely a clueless student,
could be a useless acadaemic.
http://www.ictfaculty.ir/index_e.aspx
Bob
o...@uakron.edu
> http://www.ictfaculty.ir/index_e.aspx
>
> Bob
I love their welcome speech to new students and faculty, from their
web site:
Steve
Quote begin.
Since the implementation of security and a setting full of peace and
confidence in the faculty is very important, to emphasize the
importance of maintaining a safe environment and the dignity of the
students, it is expected to observe the rules and to avoid violations.
In case of noticing or happening actions that are against the law or
the personality of the students, let the authorities of the faculty
deal with the issues.
To inform dear students who have recently been admitted, and to
perform the executive platform of the disciplinary committee of the
students, approved by the High Council of Cultural Revolution, hereby
some moral, social and legal cases that are necessary to be observed
in the faculty are pointed out.
It is necessary to mention that for each of the following violations,
punishments have been prevised (oral notification, expulsion from
faculty, etc.) ,God willing, dear students of this faculty will not
get involved in such issues.
A.Educational violations
* Cheating in the examinations
* Sending another person, or attending for somebody else in the
examinations.
* Deranging or stalling in performing educational and research
programs in the faculty.
B.General violations
* Insulting, cursing and affronting
* Theft or robbery
* Forging of deeds and documents
* Assault and battery
* Bribery and defalcation
* Causing damage or destruction of public, faculty or personal
possessions
C.Moral violations
* Using or distributing narcotic drugs, or drinking alcoholic
beverages
* Using or distributing illegal audio or video CDs
* Using or distributing pornographic books, pictures or magazines
* Disregarding Islamic dressing codes and wearing foppish clothing
D.Political violations
* Giving untrue information that is against the national interest
or public security
* Membership in belligerent and decadent groups or adherence to
such groups
* Performing actions leading firing guns or rioting
* Sitting-in or political congregating without permission from
legal authorities
* Insulting popular and religious rituals
sung...@gmail.com
> Bob
Dear Bob.
Is it important that who am I and What I'm doing!!!
Yes I am Iranian and doing SONET project. But I'm not clueless and not
in "way out of his league".
You are impolite.
Would you please tell me what wrong with the post I’ve sent is?
Phil Hobbs
Usenet newsgroups like this one tend to be fairly bruising places.
Don't take it too personally, that's just how it is. Being called
clueless if you don't specify your problem very well is actually
relatively gentle treatment, for Usenet. It's a very masculine
environment, though we do have the occasional apparent female like our
recent acquisition Sylvia, who seems to have no problems holding her own.
This is a great place to get good quality help, free, from some pretty
smart and experienced engineers. It's also a good place to collect
abuse from the collection of nutcases, wannabees, and egomaniacs that
also post here. (There's significant overlap between all four
categories, so you shouldn't necessarily ignore someone just because he
yells obscenities at odd moments or says distasteful things about
politics or religion.)
The problem is that your post didn't demonstrate that you'd actually
thought about the problem before asking. The reason that people like to
help here is that it's fun, and they have a chance to think about some
interesting engineering problems that aren't what they're working on
right now. As the old proverb puts it, "a change is as good as a rest."
Uninformed questions from people who haven't apparently put in much
effort are not fun, and are too much like what we face daily at work.
Note that this does *not* mean that you have to be an expert already,
you just have to show that you've done some serious thinking on your
own. The group sci.electronics.basics is for beginner questions, e.g.
"How does a PLL work?"
I suggest doing something like this:
1. Calculate or read up on what your jitter requirements are.
Communications is actually a pretty stringent application, so there's
lots of data out there.
2. Transform that jitter spec into a frequency-domain specification for
phase noise vs. frequency, so you know what sort of problem you're facing.
3. Do a trial design with whatever you have on hand or can find in
catalogues, calculate its performance using ordinary feedback theory,
and compare the results with (2).
4a. If you made it, you're done--if the design has interesting features,
tell us about it and join the regulars here. People who can do that
sort of thing are very welcome.
4b. If you didn't make it, ask a question like "I designed this SONET
clock recovery loop but it's 20 dB (insert actual measurement or
calculation here) worse than the spec of -120 dBc/Hz at 100 Hz offset
(insert actual numerical specification here). I have lots of loop gain
and the phase detector should be easily quiet enough. Do you have any
idea what might be wrong?"
You'll get some helpful answers and maybe some abuse, but remember that
the helpful people are treating your skills with respect and the abusive
ones don't know you personally at all. Either way, if you really aren't
clueless, come join in and help us educate the ones who are. I've
recovered from cluelessness several times myself. ;)
Cheers,
Phil Hobbs
Rich Grise
> On Jan 5, 3:58 pm, sungja...@gmail.com wrote:
>> Hi All
>> I'm going to design a PLL for the frequency of 622.08MHz. This PLL
>> should support external feedback. I've looked for such PLL muck but I
>> haven't found.
>
He wants to get an "A" on the exam without doing any homework.
Hope This Helps!
Rich
rebel
Well done Phil
I know it is early in 2009, but THAT gets my nomination for POTY.
sung...@gmail.com
>
> Phil Hobbs
Thank You Phil Hobbs.
I fill Much better right now.