Re: Magnetic vs gravity impulsing

Mike Isaacs


I have the same problem as Ian Richardson, i.e. receiving multiple copies of your messages. Six copies of the last, as well.

Mike I

In message <>, Ian Richardson via Groups.Io <> writes


I don't know why, but every time you post it comes at least 3 times!   This last
one came 6 times!!

Ian R

-----Original Message-----
From: Bepi <>
To: synchronome1 <>
Sent: Mon, 13 Jan 2020 14:07
Subject: [synchronomeelectricclock] Magnetic vs gravity impulsing

The old dear synchronome seems to be much better at measuring time than
I was expecting.
When I say measuring time here I mean intrinsically, with reference to its own
internally produced noise. Then there are all those nasty explicitly time
dependent potentials like temperature, pressure, celestial body attraction, etc,
we'll take care of them later, here I am only concerned with the internally
manufactured noise. The noise which would look statistically the same
whenever you conduct the experiment. Correct me if I am wrong.
The ones who have looked at my previous post might have noticed that I
added to the clock a magnetic impulsing system (MagImp) which seems to
be working really well, if there is interest I can describe it in detail in another
It works well in the sense that I can reduce the impulse irregular period to the
level of any other free fall period by carefully centering it in the sense of Airy's
tangent rule. With MagImp the average power is somewhat reduced too, I got
rid of the clock losses linked to the timing wheel operation, and I am always
referring to stationary states at constant amplitude of when the clock ticks
normally, I should say ticked. And with those losses we do without the
associated noise too.
In the following I will show circular error free data where the amplitude stays
the same for hours, within a few thousands of a degree, corresponding to a
fraction of a microsecond of circular error.
With the following graphs I'll compare two runs, one with magnetic impulsing
and the other with the old gravity escapement of a classic synchronome. The
clock is always the same other than the missing drawing arm, I can switch
from one impulsing scheme to the other in a matter of minutes on the same
clock, the one I purchased a few months ago on Ebay for 280 pounds.
First set of plots refer to the classic escapement:

the second set of plots refer to the magnetic impulsing case:

Compare the second graph of both set first: the average period over the
impulsing cycle vs time in hours. The average is different because the data
were taken months apart and the calibration had been changed in the
meantime, but we are not interested in the average, we are interested in the
regularity of the clock. The y scale to contain all the measurements is roughly
twice as big for the MagImp data, in fact over the experimental run the SD
(standard deviation) of the MagImp data is 4.14 μs while for the gravity arm
case the SD is 1.82 μs. The impulsing cycles are different, the MagImp cycle
consists of 5 clock periods, the synchronome of 15, but the MagImp data
have been averaged over the same number of periods, 15, before taking the
SD, so the SD comparison is fair.
The circular error variation calculated from the amplitude (green points third
graph) is shown in the red trace. In both cases the circular error contribution
to the SD is negligible, a small fraction of 1 μs.
The real surprise is in the period within the cycle, first trace. The data show
typical individual period amplitudes during the run. Those specific ones
occurred at the end of the blue trace just below the second graph, in hours
from the beginning of the run but they all look statistically the same.
Pay attention to the y scale in those graphs, always in s, the mechanical
escapement induces ms size fluctuations around the power impulse, plus a
mess after it, while the magnetic impulse induces a variation in the order of
tens of μs, if any. The MagImp impulse was not optimized as well as it could
but its amplitude deviations are nevertheless not bigger than the following
free pendulum ones. You couldn't tell when the impulse occurred and it was
only 60 to 70 ms long.
The regularity of a clock, even this fast scale regularity, is not just a matter of
size of the fluctuations but also of their correlation properties, I'll test the
autocorrelation function when I have time, but the fluctuations themselves are
a prerequisite for errors and in the mechanical case they are almost 2 orders
of magnitude larger. Did you ever look at the output of a clock timer like a
Microset with a quartz clock as an input? It's frozen on the same period
reading to the 0.1 μs figure. I don't have a Microset, I use what Luke Mester
gives away for free and an Arduino based one, but the result is the same.
Since the SD we are talking about is the one of the averages over the whole
cycle, 15 periods, what just said means that those large deviations of impulse
duration occurring at and around impulsing are just as regular and
reproducible as all the others.
I find this surprising and I would like to share it with all those people that fell
speechless in front of these data too.
Disclaimer: In this document words importing the masculine gender shall be
deemed and taken to include the feminine gender and the singular to
include the plural and the plural the singular unless the contrary as to gender
or number is expressly provided or unless the same is inconsistent with the
context and where covenants are to be entered into by more than one
person the same shall be entered into jointly.....

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[ A MIME image / jpeg part was included here. ]
Mike Isaacs

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