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Paul Taylor
electronics forum beginner
Joined: 10 Feb 2005
Posts: 45
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 Posted: Mon Jul 17, 2006 3:56 pm Post subject:
Re: FREQ COUNTER help
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"Phil Allison" <philallison@tpg.com.au> wrote in message
news:4i1p57F1nvnuU1@individual.net...
| Quote: |
"Paul Taylor"
Basically i need to count the photons in the upper atmosphere this is
done every other 1msec then transmitted back down to earth at a rate of
833khz via a telemetry system, i need to count from 1 to 65536 so a
resolution of 1 is fine.
** So you have NO idea what frequency is ??
( Hint - it is a rate expressed in cycles per second )
An electronic counter will count events ( cycles, pulses, rabbits) for
just as long as you let it.
Seems your upper frequency is really 65.536 MHz, after all.
....... Phil
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Sorry Phil I thought this was a serous newsgroup of course got the joke,
still it sounded good if you could of got one? i thought for a minute you
where referring to something else I had read about on the net where they
actually read 1 period and do some maths ect... never mind thanks for your
help any way. |
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John Fields
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3260
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| Posted: Mon Jul 17, 2006 4:10 pm Post subject:
Re: FREQ COUNTER help
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On Mon, 17 Jul 2006 16:10:31 +0100, "Paul Taylor"
<paul.taylor@uea.ac.uk> wrote:
| Quote: | "Luhan" <luhanis@yahoo.com> wrote in message
news:1153147800.910464.13150@m79g2000cwm.googlegroups.com...
Paul Taylor wrote:
Hi i am presently trying to build a counter that counts freq upto 65536
Khz
in less than 1 msec is this possible also has any one any ideas to where
i
should start thanks in advance for your help.
Paul
How about some background? What is your experience level at present?
This may not be a good project for your forray into electronics.
Luhan
Basically i need to count the photons in the upper atmosphere this is done
every other 1msec then transmitted back down to earth at a rate of 833khz
via a telemetry system, i need to count from 1 to 65536 so a resolution of 1
is fine.
|
---
Assuming that you're talking about the counter in the upper
atmosphere, you'll need a circuit which will allow the counter to
accumulate photon "hits" for 1ms every other ms at a rate of from
zero to 65536 per millisecond and, as Phil noted, that's a clock
rate of 65.536MHz. If you want a resolution of 1 photon and your
time base is 1ms its width will have to be stable to better than the
period of one cycle of 65.536MHz. That's 15.2588ns out of 1 million
nanoseconds, or about 15 parts per million over time and temperature
and voltage and...
Is that what you're looking for?
--
John Fields
Professional Circuit Designer |
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martin griffith
electronics forum Guru
Joined: 06 May 2005
Posts: 1098
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| Posted: Mon Jul 17, 2006 4:12 pm Post subject:
Re: FREQ COUNTER help
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On Mon, 17 Jul 2006 16:51:34 +0100, in sci.electronics.design "Paul
Taylor" <paul.taylor@uea.ac.uk> wrote:
| Quote: | "Luhan" <luhanis@yahoo.com> wrote in message
news:1153150487.247307.298850@i42g2000cwa.googlegroups.com...
Paul Taylor wrote:
"Luhan" <luhanis@yahoo.com> wrote in message
news:1153147800.910464.13150@m79g2000cwm.googlegroups.com...
So you already have a circuit that detects 'photons', and a telemetry
circuit, but cannot somehow design a simple counter circuit?
Sorry, does not compute.
Luhan
I have bought in a photometer which in turn is connected to a bought in
pulse amplifier discriminator (pad), this needs to be feed into a counter
to count the pulses which I am to build, the telemetry system is already in
place which I haven't built, the bottom line is I need to count the output
from the pad which counts the sodium particles and get this count back down
to earth.
Thanks
How are you getting the stuff "up there"? balloon or scud? |
martin |
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Bill Sloman
electronics forum Guru
Joined: 12 May 2005
Posts: 1080
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| Posted: Mon Jul 17, 2006 4:50 pm Post subject:
Re: FREQ COUNTER help
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John Fields wrote:
| Quote: | On 17 Jul 2006 05:24:45 -0700, bill.sloman@ieee.org wrote:
I would help if you told us more about what you are trying to do.
---
You assume you could...
|
He's at the University of Est Anglia, so he is probably sufficiently
well educated to follow the sort of stuff I dish out.
--
Bill Sloman, Nijmegen |
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John Fields
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3260
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| Posted: Mon Jul 17, 2006 5:28 pm Post subject:
Re: FREQ COUNTER help
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On 17 Jul 2006 09:50:06 -0700, bill.sloman@ieee.org wrote:
| Quote: |
John Fields wrote:
On 17 Jul 2006 05:24:45 -0700, bill.sloman@ieee.org wrote:
I would help if you told us more about what you are trying to do.
---
You assume you could...
He's at the University of Est Anglia, so he is probably sufficiently
well educated to follow the sort of stuff I dish out.
|
---
LOL, The sort of stuff you dish out is pap even morons can digest!
--
John Fields
Professional Circuit Designer |
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Michael A. Terrell
electronics forum Guru
Joined: 24 Mar 2005
Posts: 2291
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| Posted: Mon Jul 17, 2006 5:36 pm Post subject:
Re: FREQ COUNTER help
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John Fields wrote:
| Quote: |
On 17 Jul 2006 09:50:06 -0700, bill.sloman@ieee.org wrote:
John Fields wrote:
On 17 Jul 2006 05:24:45 -0700, bill.sloman@ieee.org wrote:
I would help if you told us more about what you are trying to do.
---
You assume you could...
He's at the University of Est Anglia, so he is probably sufficiently
well educated to follow the sort of stuff I dish out.
---
LOL, The sort of stuff you dish out is pap even morons can digest!
|
Come on, John, tell us how you really feel about Bill! ;-)
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida |
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Bill Sloman
electronics forum Guru
Joined: 12 May 2005
Posts: 1080
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| Posted: Mon Jul 17, 2006 10:28 pm Post subject:
Re: FREQ COUNTER help
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John Fields wrote:
| Quote: | On 17 Jul 2006 09:50:06 -0700, bill.sloman@ieee.org wrote:
John Fields wrote:
On 17 Jul 2006 05:24:45 -0700, bill.sloman@ieee.org wrote:
I would help if you told us more about what you are trying to do.
---
You assume you could...
He's at the University of Est Anglia, so he is probably sufficiently
well educated to follow the sort of stuff I dish out.
---
LOL, The sort of stuff you dish out is pap even morons can digest!
|
One does have to adjust the level to match the audience.
TTL for you, ECLinPS and GaAs for the more sophisticated.
--
Bill Sloman, Nijmegen |
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Ken Smith
electronics forum Guru
Joined: 06 May 2005
Posts: 1727
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| Posted: Tue Jul 18, 2006 12:29 am Post subject:
Re: FREQ COUNTER help
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In article <1153139085.236239.262300@35g2000cwc.googlegroups.com>,
<bill.sloman@ieee.org> wrote:
| Quote: |
Paul Taylor wrote:
Hi i am presently trying to build a counter that counts freq upto 65536 Khz
in less than 1 msec is this possible also has any one any ideas to where i
should start thanks in advance for your help.
Obviously enugh, a counter driven at 65536kHz - I presume you mean
65.536MHz - will accumulate 65536 counts in one millisecond.
|
If he doesn't, there is the option of a frequency multiplying PLL to
consider.
| Quote: | A 16-bit wide synchronous counter capable of running at 66MHz isn't
entirely trivial.
|
It doesn't need to be synchronous. Only the first stage needs to be able
to start and stop in one cycle. The rest of it can be a ripple counter.
If you wait for things to calm down after the first stage is stopped, the
rippling will finish before you read the counter.
--
--
kensmith@rahul.net forging knowledge |
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Ken Smith
electronics forum Guru
Joined: 06 May 2005
Posts: 1727
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| Posted: Tue Jul 18, 2006 12:37 am Post subject:
Re: FREQ COUNTER help
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In article <12bncevgot1dm49@corp.supernews.com>,
Meindert Sprang <ms@NOJUNKcustomORSPAMware.nl> wrote:
[...]
| Quote: | Ok, so use a 16 bit counter which you read-and-reset every ms. You need a
VHF capable prescaler (/256 or so) and then feed it into some counter or
microcontroller with an external counter input.
|
.... or ...
You can use two counter circuits and toggle between them every ms. This
way you've got a little time to latch the value away.
You really need a few more flip-flops up in the front end to make sure you
don't have any glitches happening because a count cam just at the open of
close of the 1mS gate.
Also, but not likely to be what you need:
If the frequency range is limited, you can measure the time from the start
of the 1mS to the first edge and from the end of the 1mS to the next edge
there after and assume the rest.
--
--
kensmith@rahul.net forging knowledge |
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Tim Williams
electronics forum Guru
Joined: 18 May 2005
Posts: 668
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| Posted: Tue Jul 18, 2006 2:00 am Post subject:
Re: FREQ COUNTER help
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"John Fields" <jfields@austininstruments.com> wrote in message
news:qc5nb2hda9kc8eg11t63ftbhqt6igotr52@4ax.com...
| Quote: | Please bottom post.
|
Why? His one-liner would've been at the bottom of 32 lines. You can't
rationalize that difference John. Oh, and in another thread I noticed you
getting pissy about it. Forget the valium, mmm?
Tim
--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms |
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John Fields
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3260
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| Posted: Tue Jul 18, 2006 2:28 am Post subject:
Re: FREQ COUNTER help
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On 17 Jul 2006 15:28:17 -0700, bill.sloman@ieee.org wrote:
| Quote: |
John Fields wrote:
On 17 Jul 2006 09:50:06 -0700, bill.sloman@ieee.org wrote:
John Fields wrote:
On 17 Jul 2006 05:24:45 -0700, bill.sloman@ieee.org wrote:
I would help if you told us more about what you are trying to do.
---
You assume you could...
He's at the University of Est Anglia, so he is probably sufficiently
well educated to follow the sort of stuff I dish out.
---
LOL, The sort of stuff you dish out is pap even morons can digest!
One does have to adjust the level to match the audience.
TTL for you, ECLinPS and GaAs for the more sophisticated.
|
---
The assumption you make is that you're the guru of high speed logic
while, in truth, any of us who've dealt with and built working ECL
stuff could probably easily trump your old stuff. Got a schematic
and a PCB layout you want to submit in order to prove your claim?
--
John Fields
Professional Circuit Designer |
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John Fields
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3260
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| Posted: Tue Jul 18, 2006 2:32 am Post subject:
Re: FREQ COUNTER help
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On Mon, 17 Jul 2006 21:00:28 -0500, "Tim Williams"
<tmoranwms@charter.net> wrote:
| Quote: | "John Fields" <jfields@austininstruments.com> wrote in message
news:qc5nb2hda9kc8eg11t63ftbhqt6igotr52@4ax.com...
Please bottom post.
Why? His one-liner would've been at the bottom of 32 lines. You can't
rationalize that difference John. Oh, and in another thread I noticed you
getting pissy about it. Forget the valium, mmm?
|
---
Thank you for bottom posting. :-)
--
John Fields
Professional Circuit Designer |
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Rich Grise
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3971
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| Posted: Tue Jul 18, 2006 2:50 am Post subject:
Re: FREQ COUNTER help
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On Mon, 17 Jul 2006 16:51:34 +0100, Paul Taylor wrote:
| Quote: | "Luhan" <luhanis@yahoo.com> wrote in message
Paul Taylor wrote:
"Luhan" <luhanis@yahoo.com> wrote in message
So you already have a circuit that detects 'photons', and a telemetry
circuit, but cannot somehow design a simple counter circuit?
Sorry, does not compute.
I have bought in a photometer which in turn is connected to a bought in
pulse amplifier discriminator (pad), this needs to be feed into a counter
to count the pulses which I am to build, the telemetry system is already in
place which I haven't built, the bottom line is I need to count the output
from the pad which counts the sodium particles and get this count back down
to earth.
|
It sounds like you need two counters, running more-or-less independently.
One simply counts up, every photon. The other counts up every millisecond,
at which time you read the current photon count (input the state of the
photon counter) and subtract from it the photon count at the last
one-millisecond tick; this gives you "how many photons were captured
during millisecond N", so to speak. With a micro, a millisecond is like a
year[1] - it'd be almost trivial to write some data-logging S/W that could
keep up with that.
Good Luck!
Rich
[1] In microprocessor years, of course.  |
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Sandbox Moderator
electronics forum beginner
Joined: 07 Apr 2006
Posts: 13
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| Posted: Tue Jul 18, 2006 2:55 am Post subject:
Re: FREQ COUNTER help
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On Mon, 17 Jul 2006 16:24:25 +0100, Paul Taylor wrote:
| Quote: | "John Fields" <jfields@austininstruments.com> wrote in message
On Mon, 17 Jul 2006 15:44:29 +0100, "Paul Taylor"
No, you've got to get grips with your news reader. Simply move the
cursor
to
the bottom of the original text before starting to type (after deleting
irrelevant text). Simple.
i think this is right thanks for all your help i have now mastered writing
to a newsgroup
Not quite. Next comes punctuation and capitalization. :-)
I'm going to be the master at this newsgroup business !¬)
|
****__A__**** master. ;^j
Good Luck!
Sandbox Moderator |
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Rich Grise
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3971
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| Posted: Tue Jul 18, 2006 2:58 am Post subject:
Re: FREQ COUNTER help
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On Mon, 17 Jul 2006 15:43:05 +0100, Paul Taylor wrote:
| Quote: | is this ok? i get help hopefully in the end for the problem i firsted posted
for?
|
Well, that is kinda what the newsgroup is for. If you're acting civilized,
you can usually get decent answers, but you do need to learn to ignore the
trolls. :-)
There's no stupid question, except the one that you ask three times in a
row because you don't like the other answers. ;-)
Cheers!
Rich |
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