[time-nuts] 5060A question

Dave Carlson dgcarlson at sbcglobal.net
Tue Jan 8 02:25:59 EST 2008


Since the source of the noise is the vibration of the Hot Wire Ionizer 
ribbon inside the CBT it will require using something other than pressure on 
the outer container to snuff it out. The outer steel of the CBT is rigid.


----- Original Message ----- 
From: "Bruce Griffiths" <bruce.griffiths at xtra.co.nz>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Monday, January 07, 2008 9:58 PM
Subject: Re: [time-nuts] 5060A question

Magnus Danielson wrote:
>> Hej Magnus
>> Do you mean an active noise cancellation system??
> No, you could do that too, but I was basically refering to a simple box 
> tuned
> in size to cancel at 2 kHz. Toss in a thick cloth for additional resistive
> damping.
> You could even go Helmholtz if you want.
> Simple passive cancelation. Classical acoustical approach. For 2 kHz it is 
> in
> reasnoble sizes.
> Another thing is to put heavy lead-rubber on the metal faces to make them 
> less
> of a resonator/radiator. That mod can be done inside the box.
> There are a whole bunch of other tricks. Pressing on the surfaces of the
> whining chamber will make it stiffer and provide a higher acoustical 
> impedance.
> Pressing using rubber blocks, from say silicon rubber, is known to work.
> Cheers,
> Magnus
Hej Magnus

Its a pity that the old  rho-c impedance matched high dissipation rubber
method only works under water.


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