Re: [time-nuts] Example of clocks interlocking with each other
bob@evoria.net said:
If 99 out of 100 metronomes were slower than the one fast one, I don't think
it would rule. I think you're overlooking the fact that this is a "greatest
moving mass rules" case. Notice that the board they're resting on moves.
This changes the speed of the pendulums as they move. It can either slow
the fewer ones down, or speed the fewer ones up.
Consider a kid on a swing (aka pendulum) with an adult providing the
propulsion.
The normal approach is that you put your fingers on the swing as it gets near
the top and measure when it starts back down and then add a gentle push.
That doesn't change the frequency, at least not much.
You could also push before it gets to the top.
That would speed things up. (aka increase frequency)
You could also pull as it gets near the top. (or hold on a bit)
That would slow things down. (aka decrease frequency)
Instead of pushing by hand, you could also put the whole swing and kid on a
giant shake table.
Have any of the outfits with BIG shake tables put a swing on them for their
employee type open houses or such?
In the context of metronomes, the platform is the shake table and it vibrates
at the consensus frequency with some noise. It might be fun for a time-nuts
geek[1] to measure and analyze the motion of the table and/or see how that
motion interacts with a set of metronomes.
Has anybody measured any collection of typical crystals when their power (or
whatever) is deliberately coupled? (or at least not isolated)
1] Is geek and time-nuts redundant?
--
These are my opinions. I hate spam.
And, in fact, the mass of the "shake table" has a big impact on the lock time, as does the mass of everything else besides the mass of the pendulum weights. Would there be a natural resonant frequency of the non-moving masses (shake table etc) that could prevent lockup?
Bob
From: Hal Murray hmurray@megapathdsl.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Friday, September 13, 2013 10:39 PM
Subject: Re: [time-nuts] Example of clocks interlocking with each other
In the context of metronomes, the platform is the shake table and it vibrates
at the consensus frequency with some noise. It might be fun for a time-nuts
geek[1] to measure and analyze the motion of the table and/or see how that
motion interacts with a set of metronomes.
Has anybody measured any collection of typical crystals when their power (or
whatever) is deliberately coupled? (or at least not isolated)
1] Is geek and time-nuts redundant?
--
These are my opinions. I hate spam.
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The shaking table, or base plate, is not a "non-moving mass", but is the coupling factor which transfers the energy from the sum of all the other moving masses from the strongest to the weaker. Another example of "majority rule", if you will.
Remove the resonance frequency of this coupling factor far enough from the frequency of the
driving sources, e.g. by adding mass, will reduce the coupling and will reduce lock-up, although not totally eliminate it. Think of this as adding a low-pass filter between the driving and driven units.
Acoustics Engineers and Loudspeaker Designers are familiar with this, as sound sources are frequently located close together and may interfere with each other.
Add enough mass to the coupling factor ( walls, floors, ceiling, or speaker cabinet) to lower the resonant frequency (or frequencies) is a known cure.
-- Flemming Larsen
On Sep 13, 2013, at 20:47, Bob Stewart bob@evoria.net wrote:
And, in fact, the mass of the "shake table" has a big impact on the lock time, as does the mass of everything else besides the mass of the pendulum weights. Would there be a natural resonant frequency of the non-moving masses (shake table etc) that could prevent lockup?
Bob