On Thu, 14 Feb 2008 11:00:32 -, you wrote:
Hi All,
This comment is bound to get you all going.
Maybe I'm being stupid, but why does everyone use Allan Variance and not
plan old accuracy?
I am very familiar with David Allan's full article on Allan Variance.
However Allan Variance isn't the
Something I rather miss is some good old phase or frequency plots -
especially if done at different timescales - which seem to be becoming
rather less common now.
As well as having a plot of ADEV or its relations, seeing what the
reference is doing and when is useful, and most ADEV plots
Steady boys and girls...
This discussion would be fun however, I get the feeling it would only supply
a marketing department with more copy.
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Martyn,
The stability of timing systems depends on both the type of fundamental
noise processes in a timing distribution system and how the various
processes spectrally combined through processes that shape noise such as
clock servo loops and measurements system. Consider the noise processes
of
At 06:00 AM 2/14/2008, Martyn Smith wrote...
I have an article on my web site
You might want to proof read that again. very gone Allan variance,
and there's more.
where I compare a OXCO based unit versus my rubidium's unit.
Please explain how a counter resolves to .0003 cycles in a one second
Modern counters have interpolators (now called time to
digital converters) that can measure
fractions of a cycle. Even the old Agilent 53132,
designed 15 years ago, measures any frequency to 12
significant figures in one second. For example, it will display
10 MHz to .1 Hz using a 1 second
Martyn,
I think you're comparing apples to oranges by mixing short term stability
of a 10MHz source with long term stability of a time reference, since
different processes are responsible for the observed variances.
Your data suggests that the OXCO device you've characterized is orders
of
At 10:56 AM 2/14/2008, Richard (Rick) Karlquist wrote...
Modern counters have interpolators (now called time to digital
converters) that can measure fractions of a cycle.
It appears he used an SRS620, which despite being called a counter,
really measures a time interval, and then computes the
