On 11/05/2012 06:30 AM, Tom Van Baak wrote:
Ah, I see what you mean now. Yes, that setup can give you a rough estimate of
the counter's noise floor.
I can't give you specific numbers but one danger with this sort of test is that
the input and the timebase are artificially locked together
Thanks guys,
Like usual more complicated than I thought. I was hoping that this would
cancel any stability issues common to both the reference and the signal
thus giving me best case ability. I seem to be getting numbers too good to
be true so there must be a hitch. I get an ADEV 5x10-13 at 1
Try this setup: feed the GPSDO into A and B inputs but not to the
reference. That is, use the counter internal reference to time the
difference so that you have an uncorrelated source that can span all the
interpolator's nonlinearities.
On Mon, Nov 5, 2012 at 11:42 AM, Bill Dailey
Hi
As a practical example - a SR620 will look much better reading it's own
reference than it will looking at almost anything else. That said, it's still a
good idea to make sure the counter looks good reading it's own reference. If it
doesn't look good, then you need to fix something.
Bob
Nov 2012 21:30:41 -0800
From: Tom Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Measuring gpsdo vs itself
Message-ID: C5FCD557A7C9416E8AA5E36FBF30AB2A@pc52
Content-Type: text/plain;
charset=iso-8859-1
Hi Bob,
On 11/05/2012 01:30 PM, Bob Camp wrote:
Hi
As a practical example - a SR620 will look much better reading it's own
reference than it will looking at almost anything else. That said, it's still a
good idea to make sure the counter looks good reading it's own reference. If it
doesn't
I would measure the counter both ways to characterize it, and you may
learn a little more about how it reacts.
Use its internal oscillator for the counter, apply the same 1PPS signal
to both inputs.
Use an external time base for the counter, apply the same 1 PPS to both
inputs - make sure
On Tue, 06 Nov 2012 02:14:04 +0100, Magnus Danielson
mag...@rubidium.dyndns.org wrote:
Hi Bob,
On 11/05/2012 01:30 PM, Bob Camp wrote:
Hi
As a practical example - a SR620 will look much better reading it's own
reference than it will looking at almost anything else. That said, it's
still a
If I use a gpsdo as my reference and feed the same 10MHz into a counter does
that yield the reference independent noise floor of the measuring system? Seems
to me it would look like an ideal reference with respect to the measuring
system. Thanks,
Doc
KX0O
as the reference instead of the internal XO timebase of the counter.
/tvb
- Original Message -
From: Bill Dailey docdai...@gmail.com
To: Time Nuts time-nuts@febo.com
Sent: Sunday, November 04, 2012 7:19 PM
Subject: [time-nuts] Measuring gpsdo vs itself
If I use a gpsdo as my reference and feed
of the
counter.
/tvb
- Original Message -
From: Bill Dailey docdai...@gmail.com
To: Time Nuts time-nuts@febo.com
Sent: Sunday, November 04, 2012 7:19 PM
Subject: [time-nuts] Measuring gpsdo vs itself
If I use a gpsdo as my reference and feed the same 10MHz into a counter does
docdai...@gmail.com said:
I guess what I am saying is if I discipline the counter with 10MHz and then
measure the same 10MHz. Just making sure we are on the same page.
The input signal will be at a fixed offset from the reference clock. That
offset will depend on cable lengths.
If that
as the reference instead of the internal XO timebase of the
counter.
/tvb
- Original Message -
From: Bill Dailey docdai...@gmail.com
To: Time Nuts time-nuts@febo.com
Sent: Sunday, November 04, 2012 7:19 PM
Subject: [time-nuts] Measuring gpsdo vs itself
If I use a gpsdo as my
-nuts@febo.com
Sent: Sunday, November 04, 2012 8:33 PM
Subject: Re: [time-nuts] Measuring gpsdo vs itself
I guess what I am saying is if I discipline the counter with 10MHz and then
measure the same 10MHz. Just making sure we are on the same page.
Doc
Sent from my iPad
On Nov 4, 2012, at 10:22
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