An off-topic from time to time is great, but a new email every minute
unrelated with time-nuts is a bit too much, didn't you think ?
Sorry, I don't want to be rude.
Don't apologise. Why the posters think this puerile off-topic drivel is
acceptable on the time-nuts list beats me. If they
I think someone needs to take chill-pill and relax... are you humorless or just
an idiot?
I get tired of off-topic posts too, but I'd rather laugh than grind my teeth
over something light and fluffy...
Life is too short for negative stuff... laugh a little and live
longer...
One more great unit, still may be used in brewing
beer is the degree Twaddle. = 1.005 SG.
This is a density measure, the hydrometer, so I remember.
is calibrated by dissolving one ounce quantities of copper
sulphate in a gallon of water.
What a great way of maintaining accuracy when
there is not
When your measuring, just make sure you don't get a gnat with
haemorrhoids, it can amount to a mound of a difference.
73, Steve
2009/8/20 Lux, Jim (337C) james.p@jpl.nasa.gov:
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Mark
At least an acre is acre throughout the US (I think). The real
problem was in olden France where virtually all measurements varied
from village to village. So a bushel of wheat in one locality
differed from a bushel elsewhere. Same with all of the other units.
Made for nasty trade issues once
The idea of using a standard stereo sound card interface to do Allan deviation
measurements has been discussed on the list in the past (i.e. Beat the two
signals down to some convenient audio frequency, digitize, and find zero
crossings by curve fits to the sampled data).
Several have
If isolation turns out to be a problem, I imagine it would be practical to
use two separate sound cards. It may not be practical to compensate for the
frequency-dependent effects of channel leakage, but timing/rate differences
between two independent cards should be less important and/or easier
Mark Sims wrote:
Speaking of slug-feet, I had a very direct experience with that little unit.
It had been raining here and the door mat was soaked. I did not want to track
water into the house, so I left my shoes on the back step.
The next morning, I left the house early and stepped into
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of John Miles
Sent: Friday, August 21, 2009 11:59 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Using cheap sound cards for measurements
If
Hi Lux,
Syncing inexpensive cards is a real chore (and the only reason to be
thinking about using this in the first place is to keep the cost to a
minimum, otherwise, you might as well build a special purpose little
box with counters A/Ds, and an interface)
I've had too many problems with
If isolation turns out to be a problem, I imagine it would be
practical to
use two separate sound cards. It may not be practical to
compensate for the
frequency-dependent effects of channel leakage, but timing/rate
differences
between two independent cards should be less important
That particular method is vulnerable to RF pickup from within the PC.
The coax screen should be RF grounded at both ends.
Bruce
Christian Vogel wrote:
Hi Lux,
Syncing inexpensive cards is a real chore (and the only reason to be
thinking about using this in the first place is to keep the cost
That particular method is vulnerable to a lot of things. :-P
-- john, KE5FX
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Bruce Griffiths
Sent: Friday, August 21, 2009 2:20 PM
To: Discussion of precise time and frequency
Wouldn't the cards need to be synchronized, though? Essentially,
you're still comparing the two signals with each other, just
doing it in software, rather than in hardware, in the classical
time interval counter scheme counting 1Hz (or 123Hz). Syncing
inexpensive cards is a real chore
Not the least of which is ensuring that the oscillator output can
actually drive the coax satisfactorily.
The effect of reflections due to the unterminated coax may be
significant unless the oscillator output is matched to the cable.
Bruce
John Miles wrote:
That particular method is vulnerable
Locating the zero crossing of the signal isnt the best approach.
If one uses some DSP the phase shifts between the 2 beat notes can be
measured without the sound card sampling frequency stability making a
significant contribution to the noise.
Lux, Jim (337C) wrote:
Wouldn't the cards need to be
Lux, Jim (337C) wrote:
The idea of using a standard stereo sound card interface to do Allan deviation
measurements has been discussed on the list in the past (i.e. Beat the two
signals down to some convenient audio frequency, digitize, and find zero
crossings by curve fits to the sampled
Just because the cards have the same ADC clock does not mean that they will be
sampling at the same time. There will be differences in the startup
characteristics, register programming, etc. that can affect just when the
input is sampled. They may be sampling at the same rate, but the
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Mark Sims
Sent: Friday, August 21, 2009 3:06 PM
To: time-nuts@febo.com
Subject: [time-nuts] Using cheap sound cards for measurements
Just because the cards have the same ADC
A decent home studio soundcard would have easily 60+ dB of separation
across it range and probably much higher. For the outrageous sum of around
$150 you can get the ESI Juli@ from eBay (and real dealers) with better than
60 dB of separation, below 5 Hz to 100 KHz response, differential inputs and
Modern soundcards using stereo DACs have very little shift between the
channels. Usually much less than a sample period, probably less than m-clock
period (64 to 256 X the sample period). And a high res card at 24 bits
(probably 20 usable) will give you a lot of data to chew on.
Demian Martin
Unit of land area in Denmark is the barrel, the area of land needed to
grow a barrel of grain.
Don
- Original Message -
From: Lux, Jim (337C) james.p@jpl.nasa.gov
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Thursday, August 20, 2009 5:17 PM
Lux, Jim (337C) wrote:
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Mark Sims
Sent: Friday, August 21, 2009 3:06 PM
To: time-nuts@febo.com
Subject: [time-nuts] Using cheap sound cards for measurements
Just because the cards
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bruce Griffiths
If the 2 signals are sampled at different times then there is
incomplete
cancellation of the phase noise of the offset oscillator.
This effect increases with the
Lux, Jim (337C) wrote:
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bruce Griffiths
If the 2 signals are sampled at different times then there is
incomplete
cancellation of the phase noise of the offset oscillator.
This
Could you sync the sounds cards in software?
If you feed an external 1 PPS into the unused stereo channel of
each sound card, then you can solve both card-to-card phase
differences as well as card-to-card frequency differences with
simple software fitting after, or even while, samples are being
Tom Van Baak wrote:
Could you sync the sounds cards in software?
If you feed an external 1 PPS into the unused stereo channel of
each sound card, then you can solve both card-to-card phase
differences as well as card-to-card frequency differences with
simple software fitting after, or even
On this track, what's the group opinion as to the best USB sound card?
I'm looking for one for time as well as sd radio use. Should have the best
separation, best s/n, highest digitization rate, 24 bit, etc. Any
recommendations?
Thanks
Don
Bruce Griffiths
Tom Van Baak wrote:
Could you sync the
Add balanced inputs to the list of desirable features.
Bruce
Don Latham wrote:
On this track, what's the group opinion as to the best USB sound card?
I'm looking for one for time as well as sd radio use. Should have the best
separation, best s/n, highest digitization rate, 24 bit, etc. Any
Add internal or external (5/10 MHz) clock.
/tvb
Add balanced inputs to the list of desirable features.
Bruce
Don Latham wrote:
On this track, what's the group opinion as to the best USB sound card?
I'm looking for one for time as well as sd radio use. Should have the best
separation, best
On this track, what's the group opinion as to the best USB sound
card? I'm looking for one for time as well as sd radio use. Should
have the best separation, best s/n, highest digitization rate, 24 bit,
etc. Any recommendations?
I'd be interested in not-quite-best or even far-from-best if
OK, why not?
Don
Tom Van Baak
Add internal or external (5/10 MHz) clock.
/tvb
Add balanced inputs to the list of desirable features.
Bruce
Don Latham wrote:
On this track, what's the group opinion as to the best USB sound
card?
I'm looking for one for time as well as sd radio use.
I'm looking to stay under $200, but that's why I want USB if that makes
any sense...
Don
Hal Murray
On this track, what's the group opinion as to the best USB sound
card? I'm looking for one for time as well as sd radio use. Should
have the best separation, best s/n, highest digitization
USB sound sample rates above 48 KHz are problematic. There are efforts to
overcome the limits but they end up with special drivers etc. The bulk of
the USB audio interfaces are based on Burr Broun chips which do virtually
all you need. There are some pro models for around $150 - $200 that have
On 8/21/09 8:09 PM, Tom Van Baak t...@leapsecond.com wrote:
Add internal or external (5/10 MHz) clock.
/tvb
None will have that...grin
Maybe a multiple of 48 or 44.1 kHz
Add balanced inputs to the list of desirable features.
Bruce
Don Latham wrote:
On this track, what's the
Are USB data transfer delay times an issue? IIRC they can vary quite
a lot, depending on processor loading etc.
DaveB, NZ
- Original Message -
From: Don Latham d...@montana.com
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Saturday, August 22,
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