J
John Fields
Guest
On Fri, 18 Dec 2009 13:27:15 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:
And what'll that do for him?
JF
wrote:
---
And what'll that do for him?
JF
J
John Fields
Guest
On Thu, 17 Dec 2009 21:31:35 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:
Ah, so now it's a "suitable reference source:?
Just what might that be?
---
With the crystal running at about 32768 Hz, how do you propose to make
one cycle last for 100 seconds?
Furthermore, Lissajous figures are generated by signals applied to the X
and Y axes of the scope, so how do you propose to see anything
meaningful with, say, Y running at 32768 Hz and X running at 100
seconds?
---
If, as you've stated, you have a 100s timebase which is accurate to +/-
0.1s, then it'll be accurate to one part in 1000, which is +/- 1000ppm.
Then, since there are 60 * 60 * 24 * 365.25 = 31 557 600 seconds in a
year it'll be accurate - not to "a second per year kind of accuracy" -
but to 3156 seconds = 52.6 minutes per year kind of accuracy.
---
Since most frequency counters have time-base oscillators with accuracies
much, much, better than 1000ppm, I'd say their accuracies were vastly
superior to what could be realized using the hare-brained scheme you
propose.
Wouldn't you agree?
JF
wrote:
---
Ah, so now it's a "suitable reference source:?
Just what might that be?
---
---
With the crystal running at about 32768 Hz, how do you propose to make
one cycle last for 100 seconds?
Furthermore, Lissajous figures are generated by signals applied to the X
and Y axes of the scope, so how do you propose to see anything
meaningful with, say, Y running at 32768 Hz and X running at 100
seconds?
---
---
If, as you've stated, you have a 100s timebase which is accurate to +/-
0.1s, then it'll be accurate to one part in 1000, which is +/- 1000ppm.
Then, since there are 60 * 60 * 24 * 365.25 = 31 557 600 seconds in a
year it'll be accurate - not to "a second per year kind of accuracy" -
but to 3156 seconds = 52.6 minutes per year kind of accuracy.
---
---
Since most frequency counters have time-base oscillators with accuracies
much, much, better than 1000ppm, I'd say their accuracies were vastly
superior to what could be realized using the hare-brained scheme you
propose.
Wouldn't you agree?
JF
J
John Fields
Guest
On Fri, 18 Dec 2009 17:39:35 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:
Well, even you should have figured out that the XXXXXXX was figurative
for the OP's requirements and was chosen to reflect _any_ accuracy he
might require.
---
Build an oscillator and try it, loudmouth.
I would, but I'm fresh out of watch crystals.
Anyway, just for grins I put together a 30 turn probe and held it close
to a 10k resistor with a 32768Hz TTL square wave going through it.
I could see the signal, just barely, against fluorescent background
noise, but the counter liked the noise better.
JF
wrote:
---
Well, even you should have figured out that the XXXXXXX was figurative
for the OP's requirements and was chosen to reflect _any_ accuracy he
might require.
---
---
Build an oscillator and try it, loudmouth.
I would, but I'm fresh out of watch crystals.
Anyway, just for grins I put together a 30 turn probe and held it close
to a 10k resistor with a 32768Hz TTL square wave going through it.
I could see the signal, just barely, against fluorescent background
noise, but the counter liked the noise better.
JF
W
whit3rd
Guest
On Dec 19, 12:29 pm, John Fields <jfie...@austininstruments.com>
wrote:
a frequency-shifting transformation, i.e. to look at a beat
frequency against a known frequency standard.
The standard would (best) be an atomic fountain or
(more practical) rubidium-beam or (more common) aged
calibrated crystal clock (not AT crystal, more likely GC
or other exotic type). A common frequency counter
might have an ovenized oscillator, but not 'reference-standard'
precision. If one were able to calibrate a warmed-up
counter for a day or so against NNTP time, it might
suffice for seven-figure accuracy. Or, it might not.
with the accuracy of the larger frequency that one has
applied (X-axis) to the reference (Y-axis). They aren't proportional.
'ppm' measurement of one doesn't tell the 'ppm' value of the other.
The timebase of a common frequency counter IS a hard limit,
in the sense of your 'ppm' calculation, to the accuracy of its
measurements.
wrote:
Look up 'Lissajous'. The proposed experiment is to use
a frequency-shifting transformation, i.e. to look at a beat
frequency against a known frequency standard.
The standard would (best) be an atomic fountain or
(more practical) rubidium-beam or (more common) aged
calibrated crystal clock (not AT crystal, more likely GC
or other exotic type). A common frequency counter
might have an ovenized oscillator, but not 'reference-standard'
precision. If one were able to calibrate a warmed-up
counter for a day or so against NNTP time, it might
suffice for seven-figure accuracy. Or, it might not.
No, that confuses the accuracy of the small-frequency beat
with the accuracy of the larger frequency that one has
applied (X-axis) to the reference (Y-axis). They aren't proportional.
'ppm' measurement of one doesn't tell the 'ppm' value of the other.
The timebase of a common frequency counter IS a hard limit,
in the sense of your 'ppm' calculation, to the accuracy of its
measurements.
J
John Fields
Guest
On Sat, 19 Dec 2009 13:45:36 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:
Why would you snip, from my post,:
"Furthermore, Lissajous figures are generated by signals applied to the
X and Y axes of the scope, so how do you propose to see anything
meaningful with, say, Y running at 32768 Hz and X running at 100
seconds?"
and then insert that: "Look up 'Lissajous'" crack?
---
If you've been following this thread, you should realize that what the
OP wants to do is trim a microcontroller crystal to, probably, 32768.0
Hz or, at most I'd assume, to 32768.00 Hz.
Also he has no test equipment and was considering using an oscilloscope
VS a frequency counter.
Using an oscilloscope and the methodology you suggest would certainly
bog him down and require him to acquire metrology skills and equipment
which, for his purposes, would be totally unwarranted, so what's the
point of your diatribe?
---
Had you earlier more clearly described the scheme you had in mind, that
would have fallen out immediately.
However, the scheme you describe (which is as old as the hills, by the
way) is hardly practical to implement from the OP's point of view; in my
opinion.
---
Indeed, but looking over your post again, you mentioned nothing about
the accuracy of the reference, but instead stated that a 100 second
measurement window accurate to 0.1 Hz would yield 0.001 Hz accuracy,
which is clearly not true.
How can you reconcile that?
JF
wrote:
---
Why would you snip, from my post,:
"Furthermore, Lissajous figures are generated by signals applied to the
X and Y axes of the scope, so how do you propose to see anything
meaningful with, say, Y running at 32768 Hz and X running at 100
seconds?"
and then insert that: "Look up 'Lissajous'" crack?
---
---
If you've been following this thread, you should realize that what the
OP wants to do is trim a microcontroller crystal to, probably, 32768.0
Hz or, at most I'd assume, to 32768.00 Hz.
Also he has no test equipment and was considering using an oscilloscope
VS a frequency counter.
Using an oscilloscope and the methodology you suggest would certainly
bog him down and require him to acquire metrology skills and equipment
which, for his purposes, would be totally unwarranted, so what's the
point of your diatribe?
---
---
Had you earlier more clearly described the scheme you had in mind, that
would have fallen out immediately.
However, the scheme you describe (which is as old as the hills, by the
way) is hardly practical to implement from the OP's point of view; in my
opinion.
---
---
Indeed, but looking over your post again, you mentioned nothing about
the accuracy of the reference, but instead stated that a 100 second
measurement window accurate to 0.1 Hz would yield 0.001 Hz accuracy,
which is clearly not true.
How can you reconcile that?
JF
P
Phil Allison
Guest
"John Fields"
"Phil Allison"
Just like all your fucking absurd advice.
** You are fresh out of sanity - too.
.... Phil
"Phil Allison"
** It was plucked right out of your arse.
Just like all your fucking absurd advice.
** You are fresh out of sanity - too.
.... Phil
P
Phil Allison
Guest
"John Fields"
whit3rd
The meaning was very clear.
stupidity.
** No such thing was ever said.
JF is completely off his tiny fucking head.
..... Phil
whit3rd
** The autistic JF fuckwit cannot even read.
The meaning was very clear.
** My gawd - this has gone beyond all previous limits of JF's monumental
stupidity.
** No such thing was ever said.
JF is completely off his tiny fucking head.
..... Phil
J
John Fields
Guest
On Sun, 20 Dec 2009 11:24:57 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:
That's right.
Why do you think I wrote X's, to show extreme accuracy?
---
Tell that to the folks who take my advice and wind up with working kit.
Isn't that what you call it, 'kit'?
---
Really, Phil, after all of the hydrophobic ranting you do here I really
doubt whether your judgments about what constitutes sanity and what
doesn't are at all valid.
JF
wrote:
---
That's right.
Why do you think I wrote X's, to show extreme accuracy?
---
---
Tell that to the folks who take my advice and wind up with working kit.
Isn't that what you call it, 'kit'?
---
---
Really, Phil, after all of the hydrophobic ranting you do here I really
doubt whether your judgments about what constitutes sanity and what
doesn't are at all valid.
JF
P
Phil Allison
Guest
"John Fields, Autistic "
patterns are commonly used to compare two frequencies ??
Is the great JF completely ignorant of a such a simple technique ???
Must be so - everything he says screams it.
" If you have a suitable reference frequency source, you can watch the
pretty Lissajous figure on an X/Y oscilloscope (no dual channel, no
counter) and if it goes through a cycle in 100 seconds, with 0.1 second
stopwatch accuracy, you've just made a frequency measurement with
0.001 Hz accuracy. For your 32 kHz crystal, that's a second per year
kind of accuracy.
A frequency counter is a convenient and quick solution, but
it is NOT required nor is it superior in accuracy. "
** Fraid it is all true.....
The demented JF has forgotten how to think analogue.
Cos he has forgotten how to think at all.
..... Phil
** Errr - because you repeatedly failed to comprehend how Lissajous
patterns are commonly used to compare two frequencies ??
Is the great JF completely ignorant of a such a simple technique ???
Must be so - everything he says screams it.
Here is the idea:
" If you have a suitable reference frequency source, you can watch the
pretty Lissajous figure on an X/Y oscilloscope (no dual channel, no
counter) and if it goes through a cycle in 100 seconds, with 0.1 second
stopwatch accuracy, you've just made a frequency measurement with
0.001 Hz accuracy. For your 32 kHz crystal, that's a second per year
kind of accuracy.
A frequency counter is a convenient and quick solution, but
it is NOT required nor is it superior in accuracy. "
** Fraid it is all true.....
The demented JF has forgotten how to think analogue.
Cos he has forgotten how to think at all.
..... Phil
P
Phil Allison
Guest
"John Fields is off his Head"
Just like all your fucking absurd advice.
** You are fresh out of sanity too, asshole.
Completely lost touch with reality.
.... Phil
** It was plucked right out of your arse.
Just like all your fucking absurd advice.
** You are fresh out of sanity too, asshole.
Completely lost touch with reality.
.... Phil
P
Phil Allison
Guest
"Clue Less = John Fields "
** ROTFL !!!
This is all too weird for me.
...... Phil
** ROTFL !!!
This is all too weird for me.
...... Phil
J
Jasen Betts
Guest
On 2009-12-19, John Fields <jfields@austininstruments.com> wrote:
use a tuned probe. 32768Hz crystals work good for probes.
J
John Fields
Guest
On Sun, 20 Dec 2009 11:49:34 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:
Don't be absurd.
What I question is the use of Lissajous figures in order to determine
frequencies accurately to within a few ppm more economically than by
using a frequency counter. This isn't the 1920's any more, you know.
---
Hardly; I probably learned about it while you were still floating around
in your mother's alimentary tract.
---
There are none so deaf as those that will not hear.
---
Ho-hum...
JF
wrote:
---
Don't be absurd.
What I question is the use of Lissajous figures in order to determine
frequencies accurately to within a few ppm more economically than by
using a frequency counter. This isn't the 1920's any more, you know.
---
---
Hardly; I probably learned about it while you were still floating around
in your mother's alimentary tract.
---
---
There are none so deaf as those that will not hear.
---
---
Ho-hum...
JF
J
John Fields
Guest
On Sun, 20 Dec 2009 11:53:49 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:
---
Tell that to the folks who take my advice and wind up with working kit.
(Hey, didn't I answer this one already?)
---
And you're a fit judge?
JF
wrote:
Of course it was; just like 32768.XX would've been. Your point???
---
---
Tell that to the folks who take my advice and wind up with working kit.
(Hey, didn't I answer this one already?)
---
---
And you're a fit judge?
JF
J
John Fields
Guest
On Sun, 20 Dec 2009 13:50:12 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:
Well, then, you better just stick to power supplies and audio and leave
metrology to the big boys.
JF
wrote:
---
Well, then, you better just stick to power supplies and audio and leave
metrology to the big boys.
JF
J
John Fields
Guest
On 20 Dec 2009 08:25:52 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:
So does an electret mic.
JF
---
So does an electret mic.
JF
P
Phil Allison
Guest
** No way that includes autistic retards like YOU then.
FOAD - septic fuckhead.
...... Phil
P
Phil Allison
Guest
"John Fields, Autistic LIAR "
patterns are commonly used to compare two frequencies ??
The great JF is completely ignorant of a such a simple technique.
" If you have a suitable reference frequency source, you can watch the
pretty Lissajous figure on an X/Y oscilloscope (no dual channel, no
counter) and if it goes through a cycle in 100 seconds, with 0.1 second
stopwatch accuracy, you've just made a frequency measurement with
0.001 Hz accuracy. For your 32 kHz crystal, that's a second per year
kind of accuracy.
A frequency counter is a convenient and quick solution, but
it is NOT required nor is it superior in accuracy. "
** Fraid it is all true.....
The demented JF has forgotten how to think analogue.
Cos JF has autistic dementia and cannot think at all.
..... Phil
** Errr - because you repeatedly failed to comprehend how Lissajous
patterns are commonly used to compare two frequencies ??
The great JF is completely ignorant of a such a simple technique.
Here is the idea:
" If you have a suitable reference frequency source, you can watch the
pretty Lissajous figure on an X/Y oscilloscope (no dual channel, no
counter) and if it goes through a cycle in 100 seconds, with 0.1 second
stopwatch accuracy, you've just made a frequency measurement with
0.001 Hz accuracy. For your 32 kHz crystal, that's a second per year
kind of accuracy.
A frequency counter is a convenient and quick solution, but
it is NOT required nor is it superior in accuracy. "
** Fraid it is all true.....
The demented JF has forgotten how to think analogue.
Cos JF has autistic dementia and cannot think at all.
..... Phil
W
whit3rd
Guest
On Dec 19, 4:13 pm, John Fields <jfie...@austininstruments.com> wrote:
and time it with a stopwatch with 0.1 second accuracy. A stable
pattern indicates exact small-integer-ratio frequency matching, and
an evolving pattern indicates a deviation from the match.
So, for someone working with a trimmer, you get immediate visual
feedback when looking at a Lissajous display, and the trim is
quickly done. If there's a drift, as I described, you can use simple
easily available tools (a stopwatch) to achieve quite remarkable
precision. That '.001 Hz' was not a joke, nor an error.
As to the accuracy of the 'reference', it was my thought that a
crystal out of
the box would have 5 figure accuracy, maybe 6, and that trimming
it would require a reference with much more than that (8 figures being
a good high target). My frequency counters aren't that good, and
the required gate times aren't friendly to tweaking-as-you-watch even
if they were.
I believe tuning-fork watch crystals are trimmed at the factory
with laser ablation of the metal (mass) on the tines, and, with the
recommended oscillator circuitry, should do well without any
adjustment.
Aging and temperature drifts which aren't trimmable are likely to be
significant.
What I wrote, was that one could watch a Lissajous pattern evolve
and time it with a stopwatch with 0.1 second accuracy. A stable
pattern indicates exact small-integer-ratio frequency matching, and
an evolving pattern indicates a deviation from the match.
So, for someone working with a trimmer, you get immediate visual
feedback when looking at a Lissajous display, and the trim is
quickly done. If there's a drift, as I described, you can use simple
easily available tools (a stopwatch) to achieve quite remarkable
precision. That '.001 Hz' was not a joke, nor an error.
As to the accuracy of the 'reference', it was my thought that a
crystal out of
the box would have 5 figure accuracy, maybe 6, and that trimming
it would require a reference with much more than that (8 figures being
a good high target). My frequency counters aren't that good, and
the required gate times aren't friendly to tweaking-as-you-watch even
if they were.
I believe tuning-fork watch crystals are trimmed at the factory
with laser ablation of the metal (mass) on the tines, and, with the
recommended oscillator circuitry, should do well without any
adjustment.
Aging and temperature drifts which aren't trimmable are likely to be
significant.
J
John Fields
Guest
On Mon, 21 Dec 2009 09:46:50 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:
How would YOU know?
So far all you've done is parrot whit3rd's dialogue and spew your
hydrophobic blather rather than come up with your own explanation of why
you think I'm wrong.
Typical Phil.
---
See what I mean?
JF
wrote:
---
How would YOU know?
So far all you've done is parrot whit3rd's dialogue and spew your
hydrophobic blather rather than come up with your own explanation of why
you think I'm wrong.
Typical Phil.
---
---
See what I mean?
JF