Hi,
I am an electrical engineering student and I am interested in circuit
design. Unfortunety I am not so familiar with analog design. Therefore I
want to place my question here in the newsgroup:
Is there a method to reduce jitter without the use of PLL? Where can I find
sophisticated circuits for this?
Any help, hints and comments are highly appreciated.
Greetings Simon
Before trying to give specific advice, I'll point you at a decent
introduction to the subject:
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After that, we'd need a lot more information - PLLs have jitter that is
often worse than the driving input for instance, so they are not a
panacea.
Cheers
PeteS
I used to actually enjoy Exam Week. About an hour before each test,
I'd sit under an oak tree, skim the textbook, take the test, and then
I'd have the rest of the day off. If I was in a playful mood, I'd
finish the test in a half hour and leave, which would freak everybody
else out and boost me on the curve. Having done electronics since I
was a kid, I knew what was important. To most of the other guys, all
this was a maze of equations without a lot of real meaning... I was
the *only* electronics hobbyist in my EE class. I took one electrical
machinery class, with an especially ornery instructor, where class
average on quizzes was 15%, so my 50% was an A.
He'd lecture:
"OK, will this motor rotate clockwise or counterclockwise? Show of
hands? OK, next subject..."
John
On 1/17/07 4:24 AM, in article
45ae158b$0$5720$ snipped-for-privacy@newsspool3.arcor-> Hi,
You should have begun with Google.
Yes. Google.
1. Search Google.
2. Pay some attention to the feedback filter.
Don
"John Larkin" wrote in message
There was a kid in my school who did that.. When the results can back it he
would get 150% right because he'd answered all the questions not just the 4
out of 6 that you were meant to.
Most times when I've had an exam where it was, "answer x of y questions," if
you answered more than x it was the grader's call on which x of y they'd
grade, so you'd better be quite certain you answered them all correctly.
John probably had pretty good exams... ones where, if you truly understood
the material, you could answer all the questions quickly, whereas those who
needed to use the exam as "brief periods of intense learning," as a former
professor of mine used to call them :-), could use up all the allotted time.
Better professors would also sit there and work through the exam themselves
to make sure there weren't any errors or ommissions that had slipped in at
the last minute... that was a much better scenario than when there was some
critical piece of information missing -- but you thought you just weren't
getting it somehow, and had wasted a bunch of time trying to figure it
out --, and someone would finally go up and ask the prof. who'd then tell
the class, "Oh, sorry! Use such and such a value..."
My first college room-mate was a mechanical engineering major. As
such, he was required to take a Freshman course titled "Engineering
Graphics", which had been taught by the same ancient professor for
decades. The professor allowed students to bring any materials they
wished to the final exam. So, of course, the engineering fraternity
sold a bound volume of all the problems ever given in the EG finals,
complete with worked out solutions.
There were some humorous twists: some of the solution sheets included
lines included like "Drop your pencil and pick it up", Lean back and
stretch" or "Smile and wave to the proctor". Of course, you were
supposed to perform those acts, not copy them blindly into the test
papers.
I wonder what the profs thought when a whole classful of students would
drop their pencils, or stretch, or smile and wave, simultaneously. ;-)
Cheers!
Rich
Reminds me when I was a student...the landlady's kid was a brat. He
persuaded one of my friends to do his homework. Friend wrote the answers
into his exercise book in pencil so kid could go over it in ink. One day kid
came home and announced he was in big trouble and had been sent to see the
head. It turned out that my friend had written "teacher has cheesy feet"
right in the middle of the previous nights homework...and the brat had gone
over it in ink so it was in his own writing. :-)
"Simon" schreef in bericht
news:45ae158b$0$5720$ snipped-for-privacy@newsspool3.arcor-online.net...
What have you done yourself before asking here? A lot of circuits introduce
jitter in a lot a signals and PLL is one of them. What circuit are you
talking about? Some years ago Electronics World had an article on reducing
jitter in signals. Being an electrical engineering student you should be
able to find this (and a lot more).
petrus bitbyter
Simon,
Your question should also explain a few more thigs:
1. which is the amplitude, the frequency and the shape of the signal
having this jitter
2. at least which is the magnitude order of your requested jitter
3. which is the circuit topology which is carrying this signal (IQ,
bipolar, unipolar etc)
PLL in 90% of the situations are adding a bigger jitter than a clean
low noise oscillator output may have.
Any sophysticated circuit has a limited chance to work opposed to a
simple circuit.
Remember one thing when you'll become engineer and you'll have a lot of
employeers on your hand: keep things simple in your design and in your
relations with other people.
greetings,
Vasile
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